A method and a device for a sidelink in a wireless communication system are provided. A transmission terminal supporting a sidelink performs transmission/reception beam pairing by using control information for a sidelink. The transmission terminal and a reception terminal can find an optimum transmission/reception beam pair on the basis of a method of repeatedly transmitting/receiving control information by the sidelink. Therefore, an appropriate transmission/reception beam pair can be found without repeatedly transmitting a synchronization signal. The reception terminal can provide feedback information on the received control information to the transmission terminal. The transmission terminal can determine an optimum transmission/reception beam pair on the basis of the feedback information.