To protect security of message information.

A person who desires to obtain message information inputs information for identifying individual information from an individual information input device 2 and a name, and a host 1 registers individual information in an individual information registration data base 5. A person who desires to transmit message information inputs message information and the name of a message object from a message information input device 3, and the host 1 registers the name of the message object and address information of message information in a message information registration data base 6. A person who desires to view message information inputs information for identifying individual information from the individual information input device 2, and the host 1 extracts identification information and collates the identification information with the individual information registration data base 5. If they match the message information is outputted to a message information output device 4, if the matched person has been registered in the message information registration data base 6 as the name of person the message is targeted to.