A base station forms a communication area communicable with a mobile communication network through a local network that includes the base station. The base station includes an obtaining unit that obtains a local-network address assigned to a mobile terminal in the communication area to communicate with a communication terminal in the local network; another obtaining unit that obtains a mobile-network address assigned to the mobile terminal to communicate with the mobile communication network; a storing unit that correlates and stores therein the local-network address and the mobile-network address; a receiving unit that receives, from the communication terminal, data having a destination address that is the local-network address; a converting unit that converts the destination address into the mobile-network address correlated with the local-network address and stored in the storing unit; and a transmitting unit that transmits, to the mobile terminal, the data whose destination address has been converted.