A control unit stores identification information of a cell which has received cell information and identification information of a position registration area to which the cell belongs, in association with each other, in a cell information storage area, and stores identification information of a position registration area where previous position registration has been executed, in a position registration area storage area. Then, the control unit receives, with priority, the cell information relating to the cell stored in the cell information storage area, which has been detected and which belongs to the position registration area where previous position registration has been executed.