Disclosed are a beam scanning method and a base station, the method in which generated is a code book comprising a plurality of second precoders, defined by the weighted sums of a plurality of first precoders, and in which a plurality of synchronization signals, to which applied are second precoders that are selected from the code book and differ from each other, are transmitted to a terminal over a plurality of time intervals. The synchronization signals are used in synchronization, beam scanning and cell ID acquisition of the terminal, and each weighted sum applied to the plurality of first precoders indicates a beam ID used in the beam scanning.