The present invention relates to a method and a device for reducing the power of a device in a wireless communication system supporting direct device to device (D2D) communication. A method, for transmitting a signal of a device in a wireless communication system supporting direct D2D communication according to the present invention, comprises the steps of: entering sleep mode in direct D2D communication between a device and an opponent device; if data to be transmitted to the opponent device is generated, transmitting a paging signal for the opponent device to a base station connected to the device, thereby requesting transmission of the paging signal to the opponent device; and resuming the D2D communication with the opponent device that has received the paging signal through the base station.