Wireless network control method and device as well as mobile communication system

A connection switchover between wireless network control devices (301,302,303,304) can be performed with a connected base station (201) being maintained in order to avoid a congestion when the congestion occurs in one of the wireless network control devices within a mobile communication network, network management information indicating congestion states of all wireless network control devices is acquired from a core network within the mobile communication network, a wireless network control device list is prepared in which a higher priority is assigned to the wireless network control devices in ascending order of congestion degree based on the network management information when a call request is received from one mobile terminal (100) through a base station, the wireless network control device list is notified to the mobile terminal through the base station, and the mobile terminal is enabled to select one of the wireless network control devices as a connecting destination.