An outside DTCP bridge for relaying information between an outside communication device connected to an outside network and a home communication device connected to a home network, carries out a first authentication and key exchange processing for purpose of copyright protection between the outside DTCP bridge and the home communication device as well as a second authentication and key exchange processing for purpose of copyright protection between the outside DTCP bridge and the outside communication device, and stores an identification information of the outside communication device. Then, transmission/reception of information between the home network and the outside network is carried out only when the outside communication device which made the access request is stored and both the first authentication and key exchange processing and the second authentication and key exchange processing succeed.