A resource used by a wireless terminal device to communicate with a terminal device in an internal network is appropriately managed. In a communication system 201, an internal network connection device 102 allocates, to a wireless terminal device 150, 151, its own resource for communicating with a terminal device 161 in an internal network 51, transmits data received from the wireless terminal device 150, 151 via the wireless base station device 101, to the terminal device 161, and transmits data received from the terminal device 161, to the wireless terminal device 150, 151 via the wireless base station device 101. The internal network connection device 102 or the wireless base station device 101 determines whether or not the allocation of the resource to the wireless terminal device 150, 151 should be maintained. Upon receiving a determination that the allocation of the resource should not be maintained, the internal network connection device 102 cancels the allocation of the resource.