A first base station apparatus, when newly installed, extracts cells of a second base station apparatus and its coverage cells neighboring them from neighboring cell information stored therein. The first base station apparatus notifies the second base station apparatus of the cells by a notification message. The second base station apparatus updates neighboring cell information stored therein based on the notification message. The first base station apparatus also sends a notification message to a third base station apparatus so that the third base station apparatus updates neighboring cell information stored therein.