diff --git a/.eslintrc b/.eslintrc
index 5e8c02e..801ea15 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -110,6 +110,7 @@
     "import/order": [2, {
       "groups": ["type", "builtin", "external", "internal", "parent", "sibling", "index", "object"],
       "alphabetize": { "order": "asc", "caseInsensitive": true }
-    }]
+    }],
+    "@typescript-eslint/no-non-null-assertion": "off"
   }
 }
diff --git a/package.json b/package.json
index f302d1b..eb1bace 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@technote-space/github-action-version-helper",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "description": "Version helper for GitHub Actions.",
   "keywords": [
     "github",
@@ -42,8 +42,8 @@
   "dependencies": {
     "@actions/github": "^5.0.1",
     "@octokit/openapi-types": "^11.2.0",
-    "@technote-space/github-action-helper": "^5.3.1",
-    "@technote-space/github-action-log-helper": "^0.2.1"
+    "@technote-space/github-action-helper": "^5.3.2",
+    "@technote-space/github-action-log-helper": "^0.2.2"
   },
   "devDependencies": {
     "@commitlint/cli": "^16.2.3",
@@ -51,7 +51,7 @@
     "@octokit/types": "^6.34.0",
     "@rollup/plugin-typescript": "^8.3.2",
     "@sindresorhus/tsconfig": "^2.0.0",
-    "@technote-space/github-action-test-helper": "^0.9.2",
+    "@technote-space/github-action-test-helper": "^0.9.3",
     "@types/node": "^17.0.25",
     "@typescript-eslint/eslint-plugin": "^5.20.0",
     "@typescript-eslint/parser": "^5.20.0",
diff --git a/src/utils/misc.ts b/src/utils/misc.ts
index edee6c6..44aedac 100644
--- a/src/utils/misc.ts
+++ b/src/utils/misc.ts
@@ -10,8 +10,8 @@ export const parseLine = (message: string): ChildCommitMessage | undefined => {
   }
 
   return {
-    type: matches[1],
-    message: matches[3],
+    type: matches[1]!,
+    message: matches[3]!,
     normalized: `${matches[1]}: ${matches[3]}`,
     original: trim,
   };
@@ -24,7 +24,7 @@ export const isValidMessage = (type: string, message: string, types: Array<strin
 export const parseCommitMessage = (message: string, types: Array<string>, excludeMessages: Array<string>, breakingChangeNotes: Array<string>): ParentCommitMessage | undefined => {
   const normalizedExcludeMessages = normalize(excludeMessages);
   const messages                  = message.trim().split(/\r?\n|\r/);
-  const trim                      = messages[0].trim();
+  const trim                      = messages[0]!.trim();
   const matches                   = trim.match(SEMANTIC_MESSAGE_PATTERN);
   if (!matches) {
     return undefined;
@@ -45,7 +45,7 @@ export const parseCommitMessage = (message: string, types: Array<string>, exclud
       }
     });
 
-  if (!isValidMessage(matches[1], matches[3], types, normalizedExcludeMessages) && (!children.length && !notes.length)) {
+  if (!isValidMessage(matches[1]!, matches[3]!, types, normalizedExcludeMessages) && (!children.length && !notes.length)) {
     return undefined;
   }
 
diff --git a/tsconfig.json b/tsconfig.json
index d0dbf49..2294288 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,8 +7,7 @@
       "es2020"
     ],
     "noPropertyAccessFromIndexSignature": false,
-    "noImplicitAny": false,
-    "strictNullChecks": false
+    "noImplicitAny": false
   },
   "include": [
     "src"
diff --git a/yarn.lock b/yarn.lock
index d61aae0..881295a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -379,10 +379,10 @@
   resolved "https://registry.yarnpkg.com/@sindresorhus/tsconfig/-/tsconfig-2.0.0.tgz#610e1cb8ed4e1cb7ff0cb4cb8712cd607315c152"
   integrity sha512-1nsyWtFtPpVjEnNzp2rd03BVz84BYHeW7LNYvmcj3q4jAgJL2hl0XBp3WmDFFPjFLF3w+L0XEYqhjWUTU+TCzw==
 
-"@technote-space/github-action-helper@^5.3.1":
-  version "5.3.1"
-  resolved "https://registry.yarnpkg.com/@technote-space/github-action-helper/-/github-action-helper-5.3.1.tgz#cc5ab0651baec187f1797e82b9349cf2f8ba08a8"
-  integrity sha512-UF+uF6k2rfZ2b1Kjr+mi9yif6s5w7QM5U9kcx6seImzwGZoXnE7dTZ7GoXx43MdRrc+2M01pzWyF4j/naOGgzA==
+"@technote-space/github-action-helper@^5.3.2":
+  version "5.3.2"
+  resolved "https://registry.yarnpkg.com/@technote-space/github-action-helper/-/github-action-helper-5.3.2.tgz#a7cc47da592329d242b3be6bc41e6d992bbcbc97"
+  integrity sha512-LUUq5pXF+tDM7Bcx6Je8c/s1nHq00fCdHpedxUOgQdT3nMmXN4xhxqiJGi6YZNewCbt+wBbGQ6ucpcn3GnN3cg==
   dependencies:
     "@actions/core" "^1.6.0"
     "@actions/github" "^5.0.1"
@@ -392,18 +392,18 @@
     shell-escape "^0.2.0"
     sprintf-js "^1.1.2"
 
-"@technote-space/github-action-log-helper@^0.2.1":
-  version "0.2.1"
-  resolved "https://registry.yarnpkg.com/@technote-space/github-action-log-helper/-/github-action-log-helper-0.2.1.tgz#5319d9f13add3bbaa75be9c1422cf9c986655b9f"
-  integrity sha512-IakrjNmMiaYKOcrk/id+oqvGzGXofcIYlpCUngyzOyVrsXCd2o7b/8eTSHAknGg8o82lN6KLW99Su9iIJye3hg==
+"@technote-space/github-action-log-helper@^0.2.1", "@technote-space/github-action-log-helper@^0.2.2":
+  version "0.2.2"
+  resolved "https://registry.yarnpkg.com/@technote-space/github-action-log-helper/-/github-action-log-helper-0.2.2.tgz#90bf784372a4af0fb720778b81c3b75de9b5cafa"
+  integrity sha512-5jHDxczTLgC4tCJ8Xc7+g1l3N1rEjfogYJiYMUA16a0okD27x9Ymq6pnlDsV6zfsq6bTlTBEHFWLFJgjVKkZpg==
   dependencies:
     "@actions/core" "^1.6.0"
     sprintf-js "^1.1.2"
 
-"@technote-space/github-action-test-helper@^0.9.2":
-  version "0.9.2"
-  resolved "https://registry.yarnpkg.com/@technote-space/github-action-test-helper/-/github-action-test-helper-0.9.2.tgz#8721f18658136f3c8ce27819940293d0847daec5"
-  integrity sha512-2kuw9cvI+sn768OAAtkIVZoPOqPZUptvsMlEURkG6mFWCtifzY0Qj52rzX9vuJWLEuwRu6JSldBiJnjepXmATQ==
+"@technote-space/github-action-test-helper@^0.9.3":
+  version "0.9.3"
+  resolved "https://registry.yarnpkg.com/@technote-space/github-action-test-helper/-/github-action-test-helper-0.9.3.tgz#b7e4e3bce6ebd0543000740ac297947e44de8b68"
+  integrity sha512-8h97sKU9rNteyErnzfTimnUifVE6SFa3HebzPWWeEIjt7KPPFCXrSaAIx1o+4Es1In46oOLZQRJOK1fwSKEaYg==
   dependencies:
     "@actions/core" "^1.6.0"
     "@actions/github" "^5.0.1"