The conventional wireless LAN system has the difficulties in limiting the extent to which network services are provided simply by controlling the intensity of radio wave.When the master unit 100 detects a mobile wireless terminal in its communication area (in step S100), it inquires of a plurality of slave units 200 and 300 if they are ready for communication with the mobile wireless terminal (in step S110). The master unit determines whether or not to provide network services to the mobile wireless terminal according to the combination of readiness for communication between each the slave units 200 and 300 and the mobile wireless terminal (in steps S120 and S125).