diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6408d37d..bd50ebbb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,7 +47,9 @@ jobs:
         include:
           # NB: Sync list with https://github.com/taiki-e/checkout-action/blob/HEAD/.github/workflows/ci.yml
           - os: ubuntu-22.04
+          - os: ubuntu-22.04-arm
           - os: ubuntu-24.04
+          - os: ubuntu-24.04-arm
           - os: ubuntu-22.04
             tool: major.minor.patch
           - os: ubuntu-22.04
diff --git a/main.sh b/main.sh
index b80ea6cb..28487e4d 100755
--- a/main.sh
+++ b/main.sh
@@ -740,9 +740,9 @@ for tool in "${tools[@]}"; do
             read_manifest "${tool}" "${version}"
             if [[ "${download_info}" == "null" ]]; then
                 if [[ "${rust_crate}" == "null" ]]; then
-                    bail "${tool}@${version} for '${host_os}' is not supported"
+                    bail "${tool}@${version} for '${host_arch}_${host_os}' is not supported"
                 fi
-                warn "${tool}@${version} for '${host_os}' is not supported; fallback to cargo-binstall"
+                warn "${tool}@${version} for '${host_arch}_${host_os}' is not supported; fallback to cargo-binstall"
                 case "${version}" in
                     latest) unsupported_tools+=("${rust_crate}") ;;
                     *) unsupported_tools+=("${rust_crate}@${version}") ;;
diff --git a/tools/ci/tool-list.sh b/tools/ci/tool-list.sh
index cd7fa2e1..d65b08d8 100755
--- a/tools/ci/tool-list.sh
+++ b/tools/ci/tool-list.sh
@@ -110,6 +110,12 @@ case "$(uname -s)" in
         ;;
     *) bail "unrecognized OS type '$(uname -s)'" ;;
 esac
+# See main.sh
+case "$(uname -m)" in
+    aarch64 | arm64) host_arch=aarch64 ;;
+    xscale | arm | armv*l) bail "32-bit Arm runner is not supported yet by this action; if you need support for this platform, please submit an issue at <https://github.com/taiki-e/install-action>" ;;
+    *) host_arch=x86_64 ;;
+esac
 
 tools=()
 for manifest in tools/codegen/base/*.json; do
@@ -120,9 +126,13 @@ for manifest in tools/codegen/base/*.json; do
         continue
     fi
     case "${host_os}" in
-        linux*) ;;
+        linux*)
+            if [[ "${host_arch}" != "x86_64" ]] && [[ "$(jq -r ".platform.${host_arch}_${host_os}_gnu" "${manifest}")" == "null" ]] && [[ "$(jq -r ".platform.${host_arch}_${host_os}_musl" "${manifest}")" == "null" ]]; then
+                continue
+            fi
+            ;;
         *)
-            if [[ "$(jq -r ".platform.x86_64_${host_os}" "${manifest}")" == "null" ]]; then
+            if [[ "$(jq -r ".platform.x86_64_${host_os}" "${manifest}")" == "null" ]] && [[ "$(jq -r ".platform.${host_arch}_${host_os}" "${manifest}")" == "null" ]]; then
                 continue
             fi
             ;;