diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 65a6ad9d..dbef9be6 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -49,6 +49,7 @@ jobs:
     - name: Setup Ruby
       uses: ruby/setup-ruby@v1
       with:
+        ruby-version: '3.1'
         bundler-cache: true
 
     - name: bundle exec rspec spec