There are provided a signal transmitter that generates a signal indicating execution of distance measurement and transmits the signal to a plurality of antennas, a combiner that adds a plurality of received signals that are radio signals including a response signal from the mobile station and each of which is correspondingly received by each of the antennas, a timing detector that detects a timing at which reception power for a signal added by the combiner is maximized and determines a reception timing of the response signal, a base station time calculator that determines a round trip time from transmission of the signal indicating execution of distance measurement to reception of the response signal on the basis of the reception timing and a timing of the transmission of the signal indicating execution of distance measurement, a power detector that identifies one of the antennas that has received a received signal with highest reception power among the plurality of received signals, and a distance calculator that calculates a distance between the distributed antenna base station and the mobile station on the basis of the round trip time, a delay in signal transmission to the antenna identified by the power detector, and a distance to the identified antenna.