diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
index 9deb0ec4fe..3b1aa41173 100644
--- a/.github/workflows/mingw.yml
+++ b/.github/workflows/mingw.yml
@@ -120,7 +120,7 @@ jobs:
           [Console]::OutputEncoding = [System.Text.Encoding]::GetEncoding("IBM437")
           [Console]::InputEncoding  = [System.Text.Encoding]::GetEncoding("IBM437")
           ruby -v
-          ruby ../mspec/bin/mspec -I../../tool/test -j
+          ruby -I../../tool/lib ../mspec/bin/mspec -j
 
       - uses: k0kubun/action-slack@v2.0.0
         with: