A radio base station main unit 4 and a plurality of remote transmitters and receivers 5 are connected to one another via communication cables 6. Each of the remote transmitters and receivers 5 carries out radio communications with mobile communication terminals 3 in a site 100 which is an area thereof. Each of cells 101, 102, and 103 which exhibits a predetermined calling capacity is comprised of one or more arbitrary sites 100 according to the traffic of the remote transmitters and receivers 5 therein.