A mobile communication system including a mobile relay node that is configured to relay communication between a base station and a mobile station, the system further comprising a relay node identification information management server, wherein: the server comprising means for receiving from the mobile relay node a handover request for moving the mobile relay node from one base station to another base station and making an inter-base station handover; the server comprising a duplication determination means (110, 756) configured to determine, upon reception the handover request from the mobile relay node, whether a situation where a plurality of relay nodes having the same identification information as the mobile relay node exist in a service area of the one base station occurs before the mobile relay node moves from the one base station to the another base station and makes an inter-base station handover; the server comprising identification information change means (120, 757) configured to send a request for a change of identification information to one relay node among the plurality of relay node having the same identification information as the mobile relay node when the duplication determination means (110, 756) determines that the situation where a plurality of relay nodes having the same identification information as the mobile relay node exist in the service area of the one base station occurs; the one mobile relay node comprising handover means configured to, upon reception of the request for a change of identification information from the identification information change means, make a handover of a mobile station communicating with the one relay node in a service area of the one relay node from the one relay node to the another base station and thereby continuing a service for the mobile station by the another base station; the one mobile relay node further comprising change means configured to, after the handover means make the handover of the mobile station, change the identification information of the one relay node; wherein the one mobile relay node is configured to notify the changed identification information to the another base station and to notify the server of the changed identification information, and wherein the server is configured to transmit to the one mobile relay node a response that permits an inter-base station handover, wherein the handover means (130, 956) is configured to make the inter-base station handover of the mobile relay node that moves from the one base station to the another base station; and wherein, after the inter-base station handover, the another base station is configured to transmit to the one relay node a handover request to make an inter-cell handover of the mobile station back from the base station to the one relay node and thereby restart a service by the one relay node. the server comprising means for receiving from the mobile relay node a handover request for moving the mobile relay node from one base station to another base station and making an inter-base station handover; the server comprising a duplication determination means (110, 756) configured to determine, upon reception the handover request from the mobile relay node, whether a situation where a plurality of relay nodes having the same identification information as the mobile relay node exist in a service area of the one base station occurs before the mobile relay node moves from the one base station to the another base station and makes an inter-base station handover; the server comprising identification information change means (120, 757) configured to send a request for a change of identification information to one relay node among the plurality of relay node having the same identification information as the mobile relay node when the duplication determination means (110, 756) determines that the situation where a plurality of relay nodes having the same identification information as the mobile relay node exist in the service area of the one base station occurs; the one mobile relay node comprising handover means configured to, upon reception of the request for a change of identification information from the identification information change means, make a handover of a mobile station communicating with the one relay node in a service area of the one relay node from the one relay node to the another base station and thereby continuing a service for the mobile station by the another base station; the one mobile relay node further comprising change means configured to, after the handover means make the handover of the mobile station, change the identification information of the one relay node; wherein the one mobile relay node is configured to notify the changed identification information to the another base station and to notify the server of the changed identification information, and wherein the server is configured to transmit to the one mobile relay node a response that permits an inter-base station handover, wherein the handover means (130, 956) is configured to make the inter-base station handover of the mobile relay node that moves from the one base station to the another base station; and wherein, after the inter-base station handover, the another base station is configured to transmit to the one relay node a handover request to make an inter-cell handover of the mobile station back from the base station to the one relay node and thereby restart a service by the one relay node.