A radio positioning system includes a plurality of base stations, each receiving a radio wave from a mobile terminal, and including a first base station whose position coordinates are known and a second base station whose position coordinates are unknown. The system also includes a distance measuring unit that measures a distance between the first and the second base stations based on the exchanging the radio waves; a position-coordinate calculating unit that calculates position coordinates of the second base station based on the measured distances; a determination control unit that determines a time reference station out of the base stations, and controls the time reference station to transmit a time reference pulse; and a distance-measurement control unit that calculates, using the time difference, a time difference between reception times of the wave signal at the base stations, and calculates position coordinates of the mobile terminal based on the time difference.