diff --git a/browser/dom/__snapshots__/extractCodeFiles.test.ts.snap b/browser/dom/__snapshots__/extractCodeFiles.test.ts.snap
new file mode 100644
index 0000000..9bbfb04
--- /dev/null
+++ b/browser/dom/__snapshots__/extractCodeFiles.test.ts.snap
@@ -0,0 +1,95 @@
+export const snapshot = {};
+
+snapshot[`extractCodeFiles 1`] = `
+Map {
+  "main.cpp" => {
+      blocks: [
+        {
+          endId: "63b7b1261280f00000c9bc36",
+          indent: 2,
+          lines: [
+            "#include <iostream>",
+            "",
+          ],
+          startId: "63b7b1261280f00000c9bc34",
+          updated: 1672982822,
+        },
+        {
+          endId: "63b7b1261280f00000c9bc3c",
+          indent: 2,
+          lines: [
+            "int main() {",
+            '  std::cout << "Hello, C++" << "from scrapbox.io" << std::endl;',
+            "}",
+            "",
+          ],
+          startId: "63b7b1261280f00000c9bc38",
+          updated: 1672982822,
+        },
+      ],
+      filename: "main.cpp",
+      lang: "cpp",
+    },
+  "py" => {
+      blocks: [
+        {
+          endId: "63b7b1261280f00000c9bc2a",
+          indent: 0,
+          lines: [
+            'print("Hello World!")',
+          ],
+          startId: "63b7b1261280f00000c9bc29",
+          updated: 1672982822,
+        },
+      ],
+      filename: "py",
+      lang: "py",
+    },
+  "python" => {
+      blocks: [
+        {
+          endId: "63b7b1261280f00000c9bc31",
+          indent: 1,
+          lines: [
+            \`console.log("I'm JavaScript");\`,
+          ],
+          startId: "63b7b1261280f00000c9bc30",
+          updated: 1672982822,
+        },
+      ],
+      filename: "python",
+      lang: "js",
+    },
+  "インデント.md" => {
+      blocks: [
+        {
+          endId: "63b7b1261280f00000c9bc2e",
+          indent: 1,
+          lines: [
+            "- インデント",
+            "  - インデント",
+          ],
+          startId: "63b7b1261280f00000c9bc2c",
+          updated: 1672982822,
+        },
+      ],
+      filename: "インデント.md",
+      lang: "md",
+    },
+  "コードブロック.py" => {
+      blocks: [
+        {
+          endId: "63b7b1261280f00000c9bc27",
+          indent: 0,
+          lines: [
+            'print("Hello World!")',
+          ],
+          startId: "63b7b1261280f00000c9bc26",
+          updated: 1672982822,
+        },
+      ],
+      filename: "コードブロック.py",
+      lang: "py",
+    },
+}
+`;
diff --git a/browser/dom/extractCodeFiles.test.ts b/browser/dom/extractCodeFiles.test.ts
new file mode 100644
index 0000000..436a99b
--- /dev/null
+++ b/browser/dom/extractCodeFiles.test.ts
@@ -0,0 +1,582 @@
+import { extractCodeFiles } from "./extractCodeFiles.ts";
+import { Line } from "../../deps/scrapbox.ts";
+import { assertSnapshot } from "../../deps/testing.ts";
+
+const sample: Line[] = [
+  {
+    "id": "63b7aeeb5defe7001ddae116",
+    "text": "コードブロック記法",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982645,
+    "updated": 1672982645,
+    "title": true,
+    "section": {
+      "number": 0,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b0761280f00000c9bc21",
+    "text": "ここでは[コードブロック]を表現する[scrapbox記法]を示す",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982645,
+    "updated": 1672982671,
+    "section": {
+      "number": 0,
+      "start": false,
+      "end": false,
+    },
+    "nodes": [
+      "ここでは",
+      {
+        "type": "link",
+        "unit": {
+          "page": "コードブロック",
+        },
+        "children": "コードブロック",
+      },
+      "を表現する",
+      {
+        "type": "link",
+        "unit": {
+          "page": "scrapbox記法",
+        },
+        "children": "scrapbox記法",
+      },
+      "を示す",
+    ],
+  },
+  {
+    "id": "63b7b0791280f00000c9bc22",
+    "text": "",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982648,
+    "updated": 1672982648,
+    "section": {
+      "number": 0,
+      "start": false,
+      "end": true,
+    },
+    "nodes": "",
+  },
+  {
+    "id": "63b7b12b1280f00000c9bc3d",
+    "text": "サンプル",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982826,
+    "updated": 1672982828,
+    "section": {
+      "number": 1,
+      "start": true,
+      "end": false,
+    },
+    "nodes": "サンプル",
+  },
+  {
+    "id": "63b7b12c1280f00000c9bc3e",
+    "text": " from [/villagepump/記法サンプル#61dd289e7838e30000dc9cb5]",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982828,
+    "updated": 1672982835,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": {
+      "type": "indent",
+      "unit": {
+        "whole": " from [/villagepump/記法サンプル#61dd289e7838e30000dc9cb5]",
+        "tag": " ",
+        "content": "from [/villagepump/記法サンプル#61dd289e7838e30000dc9cb5]",
+      },
+      "children": [
+        "from ",
+        {
+          "type": "link",
+          "unit": {
+            "project": "villagepump",
+            "page": "記法サンプル",
+            "line": "61dd289e7838e30000dc9cb5",
+          },
+          "children": "/villagepump/記法サンプル#61dd289e7838e30000dc9cb5",
+        },
+      ],
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc26",
+    "text": "code:コードブロック.py",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982821,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "py",
+      "filename": "コードブロック.py",
+      "indent": 1,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc27",
+    "text": ' print("Hello World!")',
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "py",
+      "filename": "コードブロック.py",
+      "indent": 1,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc28",
+    "text": "リンクなしコードブロック",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": "リンクなしコードブロック",
+  },
+  {
+    "id": "63b7b1261280f00000c9bc29",
+    "text": "code:py",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "py",
+      "filename": "py",
+      "indent": 1,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2a",
+    "text": ' print("Hello World!")',
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "py",
+      "filename": "py",
+      "indent": 1,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2b",
+    "text": "インデントつき",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": "インデントつき",
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2c",
+    "text": " code:インデント.md",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "md",
+      "filename": "インデント.md",
+      "indent": 2,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2d",
+    "text": "  - インデント",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "md",
+      "filename": "インデント.md",
+      "indent": 2,
+      "start": false,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2e",
+    "text": "    - インデント",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "md",
+      "filename": "インデント.md",
+      "indent": 2,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc2f",
+    "text": "言語を強制",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": "言語を強制",
+  },
+  {
+    "id": "63b7b1261280f00000c9bc30",
+    "text": " code:python(js)",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "js",
+      "filename": "python",
+      "indent": 2,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc31",
+    "text": '  console.log("I\'m JavaScript");',
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "js",
+      "filename": "python",
+      "indent": 2,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc32",
+    "text": "文芸的プログラミング",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982825,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": "文芸的プログラミング",
+  },
+  {
+    "id": "63b7b1261280f00000c9bc33",
+    "text": " 標準ヘッダファイルをインクルード",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": {
+      "type": "indent",
+      "unit": {
+        "whole": " 標準ヘッダファイルをインクルード",
+        "tag": " ",
+        "content": "標準ヘッダファイルをインクルード",
+      },
+      "children": "標準ヘッダファイルをインクルード",
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc34",
+    "text": "  code:main.cpp",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc35",
+    "text": "   #include <iostream>",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc36",
+    "text": "   ",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc37",
+    "text": " main函数の定義",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "nodes": {
+      "type": "indent",
+      "unit": {
+        "whole": " main函数の定義",
+        "tag": " ",
+        "content": "main函数の定義",
+      },
+      "children": "main函数の定義",
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc38",
+    "text": "  code:main.cpp",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": true,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc39",
+    "text": "   int main() {",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc3a",
+    "text":
+      '     std::cout << "Hello, C++" << "from scrapbox.io" << std::endl;',
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc3b",
+    "text": "   }",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": false,
+    },
+  },
+  {
+    "id": "63b7b1261280f00000c9bc3c",
+    "text": "   ",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982822,
+    "updated": 1672982822,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": false,
+    },
+    "codeBlock": {
+      "lang": "cpp",
+      "filename": "main.cpp",
+      "indent": 3,
+      "start": false,
+      "end": true,
+    },
+  },
+  {
+    "id": "63b7b0911280f00000c9bc23",
+    "text": "",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982673,
+    "updated": 1672982673,
+    "section": {
+      "number": 1,
+      "start": false,
+      "end": true,
+    },
+    "nodes": "",
+  },
+  {
+    "id": "63b7b0911280f00000c9bc24",
+    "text": "#2023-01-06 14:24:35 ",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982673,
+    "updated": 1672982674,
+    "section": {
+      "number": 2,
+      "start": true,
+      "end": false,
+    },
+    "nodes": [
+      {
+        "type": "hashTag",
+        "unit": {
+          "page": "2023-01-06",
+          "tag": "#",
+        },
+        "children": "#2023-01-06",
+      },
+      " 14:24:35 ",
+    ],
+  },
+  {
+    "id": "63b7b0931280f00000c9bc25",
+    "text": "",
+    "userId": "5ef2bdebb60650001e1280f0",
+    "created": 1672982674,
+    "updated": 1672982674,
+    "section": {
+      "number": 2,
+      "start": false,
+      "end": true,
+    },
+    "nodes": "",
+  },
+];
+
+Deno.test("extractCodeFiles", async (t) => {
+  await assertSnapshot(
+    t,
+    extractCodeFiles(sample),
+  );
+});
diff --git a/browser/dom/extractCodeFiles.ts b/browser/dom/extractCodeFiles.ts
new file mode 100644
index 0000000..adf2330
--- /dev/null
+++ b/browser/dom/extractCodeFiles.ts
@@ -0,0 +1,72 @@
+import { Line } from "../../deps/scrapbox.ts";
+
+/** 一つのソースコードを表す */
+export interface CodeFile {
+  /** file name */
+  filename: string;
+
+  /** language */
+  lang: string;
+
+  /** splitted code */
+  blocks: CodeBlock[];
+}
+
+/** 一つのコードブロックを表す */
+export interface CodeBlock {
+  /** 開始行のID */
+  startId: string;
+
+  /** 末尾の行のID */
+  endId: string;
+
+  /** コードブロックの最終更新日時 */
+  updated: number;
+
+  /** .code-titleのindent数 */
+  indent: number;
+
+  /** ブロック中のコード
+   *
+   * .code-titleは含まない
+   *
+   * 予めindentは削ってある
+   */
+  lines: string[];
+}
+
+/** `scrapbox.Page.lines`からcode blocksを取り出す
+ *
+ * @param lines ページの行
+ * @return filenameをkeyにしたソースコードのMap
+ */
+export const extractCodeFiles = (
+  lines: Iterable<Line>,
+): Map<string, CodeFile> => {
+  const files = new Map<string, CodeFile>();
+
+  for (const line of lines) {
+    if (!("codeBlock" in line)) continue;
+    const { filename, lang, ...rest } = line.codeBlock;
+    const file = files.get(filename) ?? { filename, lang, blocks: [] };
+    if (rest.start || file.blocks.length === 0) {
+      file.blocks.push({
+        startId: line.id,
+        endId: line.id,
+        updated: line.updated,
+        // 本文ではなく、.code-titleのインデント数を登録する
+        indent: rest.indent - 1,
+        lines: [],
+      });
+    } else {
+      const block = file.blocks[file.blocks.length - 1];
+      block.endId = line.id;
+      block.updated = Math.max(block.updated, line.updated);
+      block.lines.push([...line.text].slice(block.indent + 1).join(""));
+    }
+
+    files.set(filename, file);
+  }
+
+  return files;
+};
diff --git a/browser/dom/mod.ts b/browser/dom/mod.ts
index 9455b1a..5fda510 100644
--- a/browser/dom/mod.ts
+++ b/browser/dom/mod.ts
@@ -12,3 +12,4 @@ export * from "./cursor.ts";
 export * from "./selection.ts";
 export * from "./stores.ts";
 export * from "./pushPageTransition.ts";
+export * from "./extractCodeFiles.ts";
diff --git a/deps/scrapbox-rest.ts b/deps/scrapbox-rest.ts
index 5fde552..6e9ee49 100644
--- a/deps/scrapbox-rest.ts
+++ b/deps/scrapbox-rest.ts
@@ -25,4 +25,4 @@ export type {
   SessionError,
   Snapshot,
   TweetInfo,
-} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.6/rest.ts";
+} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.8/rest.ts";
diff --git a/deps/scrapbox.ts b/deps/scrapbox.ts
index fdb02a8..9185839 100644
--- a/deps/scrapbox.ts
+++ b/deps/scrapbox.ts
@@ -1,8 +1,8 @@
 export type {
   Line,
   Scrapbox,
-} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.6/userscript.ts";
+} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.8/userscript.ts";
 export type {
   BaseStore,
-} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.6/baseStore.ts";
+} from "https://raw.githubusercontent.com/scrapbox-jp/types/0.3.8/baseStore.ts";
 export * from "https://esm.sh/@progfay/scrapbox-parser@8.1.0";