A padlock can be opened by either one of a key and a code, and includes an indicator. When the padlock is opened by the key, the indicator is moved from a first position to a second position. The indicator is returned to the first position only when the padlock is opened by the code. The indicator has a surface provided with a first mark and a second mark so that when the indicator is disposed at the first position, the first mark is exposed and the second mark is covered by the indicator, and when the indicator is disposed at the second position, the second mark is exposed and the first mark is covered by the indicator. Thus, users can judge by the indicators if their padlocks have been unlocked.