diff --git a/src/main/kotlin/controller/api/AudioApiController.kt b/src/main/kotlin/controller/api/AudioApiController.kt
index 6530669..0e55b35 100644
--- a/src/main/kotlin/controller/api/AudioApiController.kt
+++ b/src/main/kotlin/controller/api/AudioApiController.kt
@@ -20,6 +20,13 @@
 ) {
     companion object {
         private const val PAGE_LIMIT = 50
+        private fun splitKeywords(keywords: String?): List<String>? {
+            return if (keywords?.isNotEmpty() == true) {
+                keywords?.split("\\s".toRegex())?.toList()
+            } else {
+                null
+            }
+        }
     }
 
     @GetMapping
@@ -31,10 +38,10 @@
     ): ResponseEntity<AudioListResponse> =
         ResponseEntity.ok(
             audioService.getByKeywords(
-                audioName?.split("\\s".toRegex())?.toList(),
-                artistName?.split("\\s".toRegex())?.toList(),
-                albumName?.split("\\s".toRegex())?.toList(),
-                tagName?.split("\\s".toRegex())?.toList(),
+                splitKeywords(audioName),
+                splitKeywords(artistName),
+                splitKeywords(albumName),
+                splitKeywords(tagName),
                 PAGE_LIMIT
             )
         )