A reception quality measurement method includes instructing a mobile station existing in a cell to measure a reception quality of a signal sent by a second base station forming a cell with a frequency different from a frequency of the cell of the first base station; setting a period including a synchronizing timing for the first base station, by the mobile station; setting a plurality of measurement timings in the period, and measuring reception quality of the signals sent by the second base station at each of the measurement timings, by the mobile station; comparing the reception qualities measured at the measurement timings, and selecting an optimum reception quality, by the mobile station; and reporting the selected optimum reception quality to the first base station as the reception quality of the signal sent by the second base station, by the mobile station.