diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index d7012598b..55e857cea 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -46,6 +46,8 @@ jobs:
       AWS_REGION: ${{ secrets.AWS_REGION }}
     steps:
       - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
       - name: Set up Ruby 2.6
         uses: actions/setup-ruby@v1
         with: