Provided is a method of transmitting a sidelink synchronization signal in a wireless communication system and a user equipment (UE) using the same. The method includes: receiving SLSS resource configuration information, wherein the SLSS resource configuration information configures SLSS resources of an equal position and number in each of a plurality of carriers in which carrier aggregation is performed, receiving SLSS transmission configuration information indicating whether the plurality of carriers actually transmits the SLSS using the SLSS resources, respectively and transmitting the SLSS using the SLSS resources indicated by the SLSS resource configuration information on at least one of the plurality of carriers determined based on the SLSS transmission configuration information.