A mobile communication system includes: a mobile terminal unit (UE); a radio base station (Node B) for performing communication with the mobile terminal unit via radio line; a radio controller (RNC) controlling the radio base station and physically divided to first control means (CPE) for performing signaling transfer control and second control means (UPE) for accommodating a radio base station thereunder and performing user data transfer control; and a radio base station replacement control apparatus (51) for governing control of replacement of the radio base station. Since the radio base station replacement control apparatus (51) is separately arranged in a network (RAN), a specific CPE or a terminal resource control section need not have the control function of replacement of the radio base station, and accordingly control of the replacement of the radio base station can be concentratedly performed by this radio base station replacement control apparatus.