When a GPS terminal (8) is located in a cell (1), positioning is performed by acquiring cell information and position information (ResPos) of the cell (1). Furthermore, since the ResPos acquired by the GPS terminal (8) in the cell (1) includes surrounding cell information about surrounding cells (cell 2 to cell 7), the surrounding cell information is also stored in the GPS terminal (8) in association with the ResPos acquired in the cell (1). When the GPS terminal (8) moves between a plurality of cells, positioning is performed using the ResPos stored in the cell (1) as is if the number of handovers is smaller than a predetermined threshold. On the other hand, if the number of handovers exceeds a predetermined threshold, positioning is performed using the ResPos acquired in the destination cell.