The present invention relates to a broadband wireless access system, and more particularly, to a method for a mobile station to efficiently scan a neighbor base station and apparatus therefor. According to one embodiment of the present invention, in a broadband wireless access system, a method of performing a scan, which is performed by a mobile station to scan a neighbor base station, includes the steps of receiving a scan response (AAI_SCN-RSP) message including a first interval information indicating an interval for the mobile station to receive a preamble of the neighbor base station from a serving base station and receiving the preamble from the neighbor base station in the first interval. Preferably, the first interval is set by a subframe unit.