According to one embodiment of the present specification, a method for reporting performance of a terminal in a mobile communication system includes the steps of: receiving a request for performance reporting from a base station; determining an indicator of whether a delay time related operation that the terminal supports is in correspondence with the request which corresponds to a pre-set condition; and transmitting a message including the determined indicator to the base station. According to one aspect of the present specification, the size of the performance reporting message is minimized in reporting the performance of the terminal.