diff --git a/src/main.ts b/src/main.ts
index 0aefbb0..90ec2f6 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -92,7 +92,7 @@ async function getChangedFiles(token: string, base: string, ref: string, initial
     case 'pull_request_review_comment':
     case 'pull_request_target': {
       if (ref) {
-        core.warning(`'ref' input parameter is ignored when 'base' is set to HEAD`)
+        core.warning(`'ref' input parameter is ignored when action is triggered by pull request event`)
       }
       if (base) {
         core.warning(`'base' input parameter is ignored when action is triggered by pull request event`)