diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 9bfa717..ff73733 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -35,7 +35,10 @@ jobs:
     - uses: actions/setup-go@v3
       with:
         go-version-file: go.mod
-    - run: docker build -t moco-agent:dev .
+    - name: Set up Docker Buildx
+      id: buildx
+      uses: docker/setup-buildx-action@v2
+    - run: docker buildx build --load -t moco-agent:dev .
   test:
     name: Small Tests
     strategy:
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 9355ee9..caa22b9 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -29,7 +29,24 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
-      - name: Login to ghcr.io
-        run: echo ${{ secrets.GITHUB_TOKEN }} | docker login ghcr.io -u $GITHUB_ACTOR --password-stdin
-      - run: docker build -t ghcr.io/cybozu-go/moco-agent:${GITHUB_REF#refs/tags/v} .
-      - run: docker push ghcr.io/cybozu-go/moco-agent:${GITHUB_REF#refs/tags/v}
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+        with:
+          platforms: linux/amd64,linux/arm64/v8
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Set Tag
+        id: set-tag
+        run: echo "RELEASE_TAG=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT # Remove "v" prefix.
+      - name: Build and push
+        uses: docker/build-push-action@v3
+        with:
+          platforms: linux/amd64,linux/arm64/v8
+          push: true
+          tags: ghcr.io/cybozu-go/moco-agent:${{ steps.set-tag.outputs.RELEASE_TAG }}
diff --git a/Dockerfile b/Dockerfile
index e565cd7..692df4f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,13 +1,15 @@
 # stage1: build the binary
-FROM quay.io/cybozu/golang:1.19-jammy as builder
+FROM --platform=$BUILDPLATFORM quay.io/cybozu/golang:1.19-jammy as builder
+
+ARG TARGETARCH
 
 COPY ./ .
-RUN CGO_ENABLED=0 go build -ldflags="-w -s" -a -o moco-agent ./cmd/moco-agent
-RUN CGO_ENABLED=0 go build -ldflags="-w -s" -a -o moco-init ./cmd/moco-init
-RUN CGO_ENABLED=0 go build -ldflags="-w -s" -a -o cp ./cmd/cp
+RUN GOARCH=${TARGETARCH} CGO_ENABLED=0 go build -ldflags="-w -s" -a -o moco-agent ./cmd/moco-agent
+RUN GOARCH=${TARGETARCH} CGO_ENABLED=0 go build -ldflags="-w -s" -a -o moco-init ./cmd/moco-init
+RUN GOARCH=${TARGETARCH} CGO_ENABLED=0 go build -ldflags="-w -s" -a -o cp ./cmd/cp
 
 # stage2: build the final image
-FROM scratch
+FROM --platform=$TARGETPLATFORM scratch
 LABEL org.opencontainers.image.source https://github.com/cybozu-go/moco-agent
 
 COPY --from=builder /work/moco-agent /