Antennas in an entire radio base station system are divided into two antenna groups so that each group has antennas in the number that allows convergence of reception directivity using a reference signal length. Reception weight vector calculators (112, 212) corresponding to respective antenna groups perform adaptive array processings, and corresponding array outputs are provided to a maximum ratio combining circuit (18). The maximum ratio combining circuit (18) performs maximum ratio combining of the array outputs corresponding to two antenna groups, based on weight information output from the reception weight vector calculators (112, 212).