In a network system, an internet is connected with a gateway router through a wire link, a plurality of access routers are connected with each other through wireless links, and one access router is connected with the gateway router through a wireless link. Each wireless link connects a Bluetooth device of one access router and a Bluetooth device of another access router or a Bluetooth device of the gateway router. When a wireless terminal unit is connected with one access router through one wireless link while issuing a network connect request, the gateway router functions as a gateway to the wire link, and an IP route from the wireless link connected with the wireless terminal unit to the wire link is set.