Provided are a synchronization method of first user equipment (P-UE) in a wireless communication system and user equipment using the method. The method involves receiving a V2X (vehicle-to-everything) message, sent by second user equipment (V-UE) via a second carrier, and performing synchronization on the basis of the V2X message. The first user equipment (P-UE) communicates with a base station via a first carrier, wherein the first carrier differs from the second carrier.