diff --git a/.github/workflows/chainer.yml b/.github/workflows/chainer.yml
deleted file mode 100644
index 2e8f1b01..00000000
--- a/.github/workflows/chainer.yml
+++ /dev/null
@@ -1,56 +0,0 @@
-name: chainer
-
-on:
-  schedule:
-    - cron: '0 15 * * *'
-  pull_request:
-    paths:
-      - 'chainer/**'
-      - '.github/workflows/chainer.yml'
-
-jobs:
-  examples:
-    if: (github.event_name == 'schedule' && github.repository == 'optuna/optuna-examples') || (github.event_name != 'schedule')
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ['3.9', '3.10', '3.11']
-
-    steps:
-    - uses: actions/checkout@v4
-    - name: setup-python${{ matrix.python-version }}
-      uses: actions/setup-python@v5
-      with:
-        python-version: ${{ matrix.python-version }}
-    - name: Install (apt)
-      run: |
-        sudo apt-get update
-        sudo apt-get -y install openmpi-bin libopenmpi-dev
-    - name: Install (Python)
-      run: |
-        python -m pip install --upgrade pip
-        pip install --progress-bar off -U setuptools
-        pip install git+https://github.com/optuna/optuna.git
-        python -c 'import optuna'
-        pip install git+https://github.com/optuna/optuna-integration.git
-        python -c 'import optuna_integration'
-
-        pip install -r chainer/requirements.txt
-    - name: Run examples
-      run: |
-        python chainer/chainer_simple.py
-        python chainer/chainer_integration.py
-      env:
-        OMP_NUM_THREADS: 1
-    - name: Run multi-node examples
-      run: |
-        export OMPI_MCA_rmaps_base_oversubscribe=yes
-        STORAGE_URL=sqlite:///example.db
-        for file in `find chainer -name 'chainermn_*.py'`
-        do
-          echo $file
-          STUDY_NAME=`optuna create-study --storage $STORAGE_URL`
-          mpirun -n 2 -- python $file $STUDY_NAME $STORAGE_URL > /dev/null
-        done
-      env:
-        OMP_NUM_THREADS: 1