diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index dbace9c3..ff700dc1 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: cmake
-      run: cmake -S . -B build
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug
     - name: build
       run: cmake --build build --parallel 10
     - name: test
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 77927966..aa2aa1da 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: cmake
-      run: cmake -S . -B build
+      run: cmake -S . -B build -D CMAKE_BUILD_TYPE=Debug
     - name: build
       run: cmake --build build --parallel 10
     - name: test
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index d3fb8cbd..81517fa6 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -10,8 +10,8 @@ jobs:
     steps:
     - uses: actions/checkout@v1
     - name: cmake
-      run: cmake -S . -B build -G "Visual Studio 16 2019"
+      run: cmake -S . -B build -G "Visual Studio 16 2019" -D CMAKE_BUILD_TYPE=Debug
     - name: build
       run: cmake --build build --parallel 10
     - name: test
-      run: cd build ; ctest -j 10 -C Release
+      run: cd build ; ctest -j 10 -C Debug