diff --git a/.github/workflows/test-doc-build.yml b/.github/workflows/test-doc-build.yml
index f594ace..c7669df 100644
--- a/.github/workflows/test-doc-build.yml
+++ b/.github/workflows/test-doc-build.yml
@@ -15,7 +15,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
+          ruby-version: 4.0.0
       - name: Install dependencies
         run: |
           bundle install