When handover control is performed in a wireless communication system in which a plurality of base stations and a plurality of mobile stations communicate wirelessly, the necessary radio resources are secured beforehand in a handover-destination radio base station before handover is performed, and handover is executed thereafter. In order to secure the radio resources, one or more mobile stations that are already communicating via the handover-destination base station are forcibly handed over to another radio base station, whereby the radio resources of the handover-destination radio base station are secured. This is followed by executing handover.