diff --git a/main.py b/main.py
index 71cd93b..27c9377 100644
--- a/main.py
+++ b/main.py
@@ -7,7 +7,17 @@
 from tkinter import messagebox
 
 
-ALARM_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "alarm", "alarm.wav")
+ALARM_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "alarm")
+SUPPORTED_FORMATS = (".mp3", ".wav", ".ogg", ".flac")
+
+def get_alarm_path():
+    if os.path.exists(ALARM_DIR):
+        for file in os.listdir(ALARM_DIR):
+            if file.lower().endswith(SUPPORTED_FORMATS):
+                return os.path.join(ALARM_DIR, file)
+    return os.path.join(ALARM_DIR, "alarm.wav")
+
+ALARM_PATH = get_alarm_path()
 
 ctk.set_appearance_mode("light")
 ctk.set_default_color_theme("blue")
@@ -261,12 +271,13 @@ def _enterTimesup(self):
             self._sendNotification()
 
     def _startAlarm(self):
-        if not os.path.exists(ALARM_PATH):
-            print(f"[Warning] Alarm file not found: {ALARM_PATH}")
+        alarm_path = get_alarm_path()
+        if not os.path.exists(alarm_path):
+            print(f"[Warning] Alarm file not found: {alarm_path}")
             return
         try:
-            mixer.music.load(ALARM_PATH)
-            mixer.music.play(loops=-1)  # -1 無限循環
+            mixer.music.load(alarm_path)
+            mixer.music.play(loops=-1)
         except Exception as e:
             print(f"[Warning] Failed to play alarm: {e}")
 
@@ -309,4 +320,4 @@ def _onCloseWindow(self):
     root = ctk.CTk()
     app = TimerApp(root)
     root.mainloop()
-    
\ No newline at end of file
+