A source base station (SeNB) composes a handover request message including information of which at least one or more CC formed for a user terminal (UE) and information about the performance of the UE associated with at least one or more CC and transmits the handover message to a target base station (TeNB) and the TeNB transmits to the SeNB a handover request response message including at least one CC allocation information as information for the CC which the UE uses thereby or CC allocation information and a CC activation indicator associated with the CC allocation information, and an activation composition indicator having a bit length with respect to the allocated CCs. Packet loss due to the handover is minimized by enabling the UE to rapidly use the CC(s) to be used in the TeNB as the moved cell and transmission efficiency of a system can be enhanced thereby.