diff --git a/.github/workflows/cleanup.yml b/.github/workflows/cleanup.yml
index 5f7c021..d0cdc5f 100644
--- a/.github/workflows/cleanup.yml
+++ b/.github/workflows/cleanup.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Cleanup
         run: |
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index b5138d0..3cb8fff 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -40,7 +40,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
diff --git a/.github/workflows/gh_pkg.yaml b/.github/workflows/gh_pkg.yaml
index 5e8dc25..3a81135 100644
--- a/.github/workflows/gh_pkg.yaml
+++ b/.github/workflows/gh_pkg.yaml
@@ -15,7 +15,7 @@ jobs:
       packages: 'write'
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       # .npmrc ファイルをセットアップして GitHub Packages に公開する
       - uses: actions/setup-node@v6
diff --git a/.github/workflows/npm_pkg.yaml b/.github/workflows/npm_pkg.yaml
index 7c92896..5c4b45b 100644
--- a/.github/workflows/npm_pkg.yaml
+++ b/.github/workflows/npm_pkg.yaml
@@ -27,7 +27,7 @@ jobs:
           REL_NAME: ${{ github.event.release.name }}
           TAG_NAME: ${{ github.event.release.tag_name }}
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       # npm に公開するように .npmrc ファイルを設定する
       - uses: actions/setup-node@v6
diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index b1633e4..5ad370f 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -17,7 +17,7 @@ jobs:
         node-version: [18.x, 20.x, 22.x]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v6