Provided are a method for transmitting a relay signal for V2X communication in a wireless communication system and a device using the same. Specifically, a terminal receives allocation information of a first relay resource and a second relay resource for a communication group from a base station. A first terminal receives a data signal through a reception beam for the first relay resource from a second terminal. The first terminal transfers the data signal to a third terminal through a transmission beam for the first relay resource. Further, the first terminal transmits an ACK/NACK for the data signal to the second terminal through a transmission beam for the second relay resource. The reception beam for the first relay resource is symmetrical to the transmission beam for the second relay resource. The transmission beam for the first relay resource is symmetrical to a reception beam for the second relay resource.