A method and an apparatus for forming a beam in an antenna array are disclosed. The method for forming a beam in an antenna array comprises the steps of: forming a first beam pattern in a first band on the basis of a single-band antenna aggregation and a multi-band antenna aggregation; and forming other beam patterns in bands other than the first band on the basis of the multi-band antenna aggregation, wherein the single-band antenna aggregation includes a plurality of single-band antennas which operate only in the first band, the multi-band antenna aggregation includes multi-band antennas which operate in a plurality of bands including the first band, and the antenna array may be arranged in a two-dimensional plane such that distances between the plurality of single-band antennas and the plurality of multi-band antennas are constant.