diff --git a/.github/workflows/manifest.yml b/.github/workflows/manifest.yml
index 05a73440..1d9775f8 100644
--- a/.github/workflows/manifest.yml
+++ b/.github/workflows/manifest.yml
@@ -32,7 +32,7 @@ concurrency:
 
 jobs:
   manifest:
-    uses: taiki-e/github-actions/.github/workflows/gen.yml@75415970465917c31d702710acd9c9248b9af314 # main
+    uses: taiki-e/github-actions/.github/workflows/gen.yml@a6df8c9ea0038c730f138f0f849d692cf387ea4e # main
     permissions:
       contents: write # for creating branch for pr
       pull-requests: write # for gh pr review --approve
@@ -46,3 +46,4 @@ jobs:
       automerge: true
       install-rust: true
       install-cosign: true
+      install-parse-changelog: true
diff --git a/tools/ci/manifest.sh b/tools/ci/manifest.sh
index 112babcb..29b2696e 100755
--- a/tools/ci/manifest.sh
+++ b/tools/ci/manifest.sh
@@ -30,9 +30,14 @@ for manifest in manifests/*.json; do
     git stash pop
     new_version=$(jq -r '.latest.version' "${manifest}")
     if [[ "${old_version}" != "${new_version}" ]]; then
-      # TODO: If there is a line about updating the same tool in the "Unreleased" section, replace it.
+      unreleased=$(parse-changelog CHANGELOG.md Unreleased)
       msg="Update \`${name}@latest\` to ${new_version}"
-      sed -Ei "s/^## \\[Unreleased\\]/## [Unreleased]\\n\\n- ${msg}./" CHANGELOG.md
+      if grep -Eq "^- Update \`${name}@latest\` to " <<<"${unreleased}"; then
+        # If there is a line about updating the same tool in the "Unreleased" section, replace it.
+        sed -Ei "0,/^- Update \`${name}@latest\` to .*/s//- ${msg}./" CHANGELOG.md
+      else
+        sed -Ei "s/^## \\[Unreleased\\]/## [Unreleased]\\n\\n- ${msg}./" CHANGELOG.md
+      fi
       git add "${manifest}" CHANGELOG.md
     else
       msg="Update ${name} manifest"