A base station control portion 200 selects one or plural signals from signals received by plural settable communication paths in accordance with the state of the wave. A wireless communication apparatus 110 communicates with a wireless terminal 300 and a wired communication network. When the wireless communication apparatus 110 receives a request for upgrading software from a network management device 250, the wireless communication apparatus 110 controls the state of the transmission wave of a wireless interface so as to switch a communication path in which communication services are being provided to another wireless communication apparatus 110 without blackouts, rewrites the set software to software having been received through a wired interface in advance, returns the state of the transmission wave of the wireless interface and upgrades software without blackouts of the supply of communication services to the wireless terminal 300.