diff --git a/.github/workflows/format_check.yml b/.github/workflows/format_check.yml
index cb8f7b8..6ea1db9 100644
--- a/.github/workflows/format_check.yml
+++ b/.github/workflows/format_check.yml
@@ -30,7 +30,7 @@ jobs:
         with:
           persist-credentials: false
           fetch-depth: 0
-          ref: ${{ github.event.pull_request.head.ref }}
+          ref: refs/pull/${{ github.event.pull_request.number }}/head
 
       - uses: coursier/cache-action@95e5b1029b6b86e7bac033ee44a0697d8a527d2d