A mobile communication method when a mobile station performs handover from a cell subordinate to a first radio base station (eNB) to a cell subordinate to a second radio base station (HeNB2), in a mobile communication system provided with the first radio base station (eNB) and the second radio base station (HeNB2), the second radio base station (HeNB2) being capable of operating either in "Open", "Closed", or "Hybrid" and, being connected under a gateway device (HeNB-GW), the method comprising: a step of determining, by the mobile station, whether the mobile station is a registered mobile station or an unregistered mobile station in the second radio base station (HeNB2), based on Closed Subscriber Identifier (CSG-ID) included in broadcast information transmitted by the second radio base station (HeNB2) and an allowed CSG-ID list managed by the mobile station; a step of transmitting, by the mobile station, a measurement report including a determination result, to the first radio base station (eNB); a step of transmitting (S1003A), by a mobile switching center, a handover request signal including predetermined information indicating whether the mobile station is a registered mobile station or an unregistered mobile station in the second radio base station (HeNB2), to the gateway device (HeNB-GW); a step of transmitting (S1003B), by the gateway device (HeNB-GW), the handover request signal including the predetermined information, to the second radio base station (HeNB2); a step of performing, by the second radio base station (HeNB2), a resource assignment process for registered mobile station, on the mobile station, when the predetermined information indicates that the mobile station is the registered mobile station in the second radio base station (HeNB2) and the second radio base station (HeNB2) operates in the "Hybrid"; and a step of performing, by the second radio base station (HeNB2), a resource assignment process for unregistered mobile station, when the predetermined information indicates that the mobile station is the unregistered mobile station in the second radio base station (HeNB2) and the second radio base station (HeNB2) operates in the "Hybrid". a step of determining, by the mobile station, whether the mobile station is a registered mobile station or an unregistered mobile station in the second radio base station (HeNB2), based on Closed Subscriber Identifier (CSG-ID) included in broadcast information transmitted by the second radio base station (HeNB2) and an allowed CSG-ID list managed by the mobile station; a step of transmitting, by the mobile station, a measurement report including a determination result, to the first radio base station (eNB); a step of transmitting (S1003A), by a mobile switching center, a handover request signal including predetermined information indicating whether the mobile station is a registered mobile station or an unregistered mobile station in the second radio base station (HeNB2), to the gateway device (HeNB-GW); a step of transmitting (S1003B), by the gateway device (HeNB-GW), the handover request signal including the predetermined information, to the second radio base station (HeNB2); a step of performing, by the second radio base station (HeNB2), a resource assignment process for registered mobile station, on the mobile station, when the predetermined information indicates that the mobile station is the registered mobile station in the second radio base station (HeNB2) and the second radio base station (HeNB2) operates in the "Hybrid"; and a step of performing, by the second radio base station (HeNB2), a resource assignment process for unregistered mobile station, when the predetermined information indicates that the mobile station is the unregistered mobile station in the second radio base station (HeNB2) and the second radio base station (HeNB2) operates in the "Hybrid".