34 and 34 2 34 are 34 none 34 the first and third rows whereas storage area numbers and secret numbers are registered with regard to the subaddresses 34 1 34 and 34 3 34 as mentioned above whether or not confidentiality information has been registered is determined at step s503 when information has been registered or in other words when a storage area for receiving a confidential document has been set in the memory unit 208 this is regarded as meaning that the received document requires confidential treatment and therefore the received document is so treated confidential treatment on the receiving side is decided by whether or not the sending side has transmitted a subaddress in relation to transmission of the document confidential treatment is not implemented in a case where no storage area number has been registered that is if the decision rendered at step s503 is no meaning that confidentiality information has not been registered on the receiving side as a result of which a storage area has not been set in the memory unit 208 this is regarded as signifying that the received document is not desired to be treated confidentially and therefore the program proceeds to step s502 to execute ordinary processing described above the program returns at the conclusion of this processing if a yes decision is rendered at step s503 namely that confidentiality information has been registered.