A mobile communication system has a plurality of nodes, hierarchically connected to each other, including a source base station and a target base station. A U-plane management station includes detecting unit detecting a handover for the mobile terminal, and a Bi-casting unit redundantly transmitting, when detecting the handover for the mobile terminal, the same user data addressed to the mobile terminal toward both of the source base station and the target base station. The target base station includes a retaining unit receiving the user data addressed to the mobile terminal, which is transmitted by the U-plane management station, and retaining the user data, and a wireless transmitting unit wirelessly transmitting, when the mobile terminal is wirelessly connected after moving, the user data requested by the mobile terminal in the user data retained by the retaining unit and addressed to the mobile terminal.