A base station receives from a mobile station, a reference signal that includes two or more sequences of a fixed length and calculates, as information for uplink signal synchronization at the mobile station, delay with respect to a reference time of the reference signal. The base station includes a first correlator that calculates the delay and a first correlation value calculated by correlating known sequences and the reference signal received during a first interval set based on the reference time and including a period equivalent to the fixed length; a second correlator that calculates a second correlation value by correlating the known sequences and the reference signal received during a second interval different from the first interval and including a period equivalent to the fixed length; and a corrector that based on a comparison result of the first and the second correlation values, determines whether to correct the calculated delay.