diff --git a/src/main.ts b/src/main.ts
index 8320287..a2f7cd8 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -87,7 +87,7 @@ async function getChangedFiles(token: string, base: string, ref: string, initial
   const prEvents = ['pull_request', 'pull_request_review', 'pull_request_review_comment', 'pull_request_target']
   if (prEvents.includes(github.context.eventName)) {
     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`)