diff --git a/.github/workflows/build-and-attach-pdf-on-pr.yml b/.github/workflows/build-and-attach-pdf-on-pr.yml
index 6b6c166..b98d9a5 100644
--- a/.github/workflows/build-and-attach-pdf-on-pr.yml
+++ b/.github/workflows/build-and-attach-pdf-on-pr.yml
@@ -22,7 +22,7 @@ jobs:
     steps:
       # リポジトリをチェックアウト
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Node.jsをセットアップ
       - name: Setup Node.js
diff --git a/.github/workflows/publish-and-release-pdf.yml b/.github/workflows/publish-and-release-pdf.yml
index a19ffac..a1b6b6a 100644
--- a/.github/workflows/publish-and-release-pdf.yml
+++ b/.github/workflows/publish-and-release-pdf.yml
@@ -26,7 +26,7 @@ jobs:
 
       # リポジトリをチェックアウト
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Node.jsをセットアップ
       - name: Setup Node.js
diff --git a/.github/workflows/update-makefile.yml b/.github/workflows/update-makefile.yml
index e6d0e2d..09b28c8 100644
--- a/.github/workflows/update-makefile.yml
+++ b/.github/workflows/update-makefile.yml
@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0