Disclosed are: a method for a terminal to transmit a sidelink signal in a wireless communication system that supports sidelink according to various embodiments; and a device for same. Disclosed are a method for a terminal to transmit a sidelink signal and a device for same, the method including: a step for determining a plurality of candidate resources on the basis of reserved resources sensed in a predetermined resource pool and the reception intensities of received signals; a step for determining, on the basis of the attributes of a sidelink signal or the attributes of packets included in the sidelink signal, whether to perform additional carrier sensing for selecting a transmission resource from among the plurality of candidate resources; a step in which if the carrier sensing is performed, the transmission resource is selected after performing the carrier sensing on the plurality of candidate resources until a prescribed timing; and a step in which the sidelink signal is transmitted from the selected transmission resource.