When an access process request signal for access to a connection network, from a terminal which exists in the same coverage area shared by a plurality of radio base stations, is received by one of the radio base stations, an access point base station is determined according to the resource information of the radio base stations by the connection network so as to transmit to the terminal, an access process base station modification request signal which requests that the access process request signal be transmitted to the radio base station that serves as the determined access point base station.