diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 32149a8d..d18832af 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,7 +13,7 @@ jobs:
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2.3.4
 
     - name: Set up Ruby ${{ matrix.ruby }}
       uses: actions/setup-ruby@v1
diff --git a/.github/workflows/gempush.yml b/.github/workflows/gempush.yml
index 8fd43a6d..44599783 100644
--- a/.github/workflows/gempush.yml
+++ b/.github/workflows/gempush.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v2.3.4
     - name: Set up Ruby 2.6
       uses: actions/setup-ruby@v1
       with: