This invention provides a wireless network system including a logically or physically separated wired network, a wireless base station connected to the wired network, and a plurality of wireless mobile terminals which performs wireless communication with the wireless base station. The wireless base station used in this system includes a wired communication unit which is connected to a wired network, a wireless communication unit which performs wireless communication using one radio frequency, and a wired line/wireless channel bridging function. The wireless base station also includes a control unit which controls one wireless communication unit to send out packets storing pieces of information corresponding to a plurality of virtual wireless networks so as to form a plurality of virtual wireless networks.