A method for a User Equipment (UE) configured to perform device-to-device (D2D) communication in a wireless communication system, includes receiving, from a base station, a message including information on available resources to transmit D2D data for the UE in a condition; and transmitting, to a second UE, the D2D data based on a part of the available resources, wherein the condition is that the UE is in an out-sync condition.