A mobile communication system can predict a temporary access concentration to a particular wireless base station, select an appropriate wireless base station and assign down channels for each mobile terminal. In respective wireless base stations, switching scheduling to a channel congestion avoidance mode is performed by checking the obtained use history of respective wireless base stations to determine the periodicity regarding the channel congestion of the respective wireless base stations. Once switched to the channel congestion avoidance mode, a wireless base station for each mobile terminal is selected based on idle channel conditions of surrounding wireless base stations and moving direction characteristics of mobile terminals currently connected to the wireless base station. The only down channel of each mobile terminal is connected to the selected wireless base station, and the wireless communication is established.