Provided in one disclosure of the present specification is a method for transmitting a detection signal from user equipment (UE). The method comprises the steps of: driving a mobility management (MM) delay time timer, when the MM delay time timer is received by the UE from a mobility management entity (MME) in a network; confirming the priority for detecting at least one other UE, when detection of the at least one other UE is required before the MM delay time timer expires; and randomly selecting a resource based on a shared resource pool included in system information, which is broadcasted from a base station, and then transmitting to the at least one other UE a detection signal including a proximity service code from the randomly selected resource, when the detection of the at least one other UE is considered to have high priority or to be urgent.