To provide a route information management devicewhich suitably manages route information.

A communication control device 10 includes a plurality of ports for connections with a plurality of networks, a database stored with an IP address of a communication device and a port to which communication data to be transmitted to the communication device should be output in a correspondence state; a retrieval circuit which retrieves the IP address of a communication device as the destination of the acquired communication data from the database; a processing executing circuit which sends out the communication data, from the port made to correspond to the IP address of the communication device as the destination of the communication data; and a decision unit sending the communication data transmitted to a route calculating device 856 which does not send to the retrieval circuit, but to the route calculating device 856. The route calculating device 856 includes a calculation unit 857, which acquires route information transmitted from other routers from the decision unit and calculates a route table based on the route information, and a database updating unit 858 which reflects the route table calculated by the calculation unit 857 on the database.