In a mobile-communication system including a base-transceiver station (BTS), a visitor-location register (VLR), and controllers for controlling a mobile station (MS), the controllers including at least one mobile-switching center (MSC) each controlling at least one radio-network controller (RNC), when a location-registration request is transmitted from the MS, it is determined whether or not being located in a controlled area of the controllers is allowed. If being located in a controlled area of one of the controllers is not allowed, re-location registration is performed for a cell placed under control of the other controller. If it is difficult to perform the re-location registration, forced-location registration is performed so that the location of a different MS is registered with a different cell. Subsequently, it becomes possible to decrease the state where originating calls are made with difficulty when subscribers are concentrated in a predetermined area.