Disclosed in the present application is a method for a terminal transmitting a scheduling assignment (SA) for direct device-to-device communication in a wireless communication system. More specifically, the method comprises the steps of: determining whether data to be transmitted using the direct device-to-device communication is present; determining whether to transmit the SA according to a resource allocation mode for the direct device-to-device communication, when the data is not present; and transmitting a first SA when the resource allocation mode is a first mode, wherein the resource allocation mode includes the first mode in which a resource for the direct device-to-device communication is allocated by a base station, and a second mode in which a resource for the direct device-to-device communication is allocated through a random selection by the terminal.