A disclosure of the present specification provides a method by which a wireless device performs measurement. The method can include: a step for receiving information about a plurality of synchronization signal (SS) burst set periods from a serving cell; and a step for performing measurements on a plurality of neighbor cells on the basis of a measurement gap length (MGL) and a measurement gap repetition period (MGRP) set on the basis of the plurality of SS burst set periods. The MGL and the MGRP can be set in consideration of one or more among L, representing the largest value among the SS burst set periods, S, representing the smallest value among the SS burst set periods, D, representing a default value of the SS burst set period, and R, representing a radio frequency (RF) switching time of the wireless device.