A base station apparatus for performing radio communication with a mobile station in a cell having a plurality of sectors performs a MIMO transmission using an antenna selected from among the antennas provided in each of two sectors when the mobile station moves in the vicinity of the boundary between the sectors. A base station apparatus for performing the radio communication with a mobile station in a cell having no sector structure performs a MIMO transmission using two or more antennas selected from among the antennas when the mobile station moves.