Disclosed, according to various embodiments, are a method by which a first terminal performs beam pairing in a wireless communication system for supporting a sidelink, and an apparatus. Disclosed are a method and an apparatus therefor, the method comprising the steps of: determining a first resource region for communication through the exchange of a discovery message in a first discovery resource region; and transmitting a sidelink signal to a second terminal in the first resource region, wherein the first discovery resource region is linked, in advance, with a plurality of resource regions for communication, and the first terminal determines, on the basis of the measured value of the sidelink signal which is less than a first threshold value, a resource region in which a beam pair is reselected.