To prevent transmission of a useless mail by preventing an incorrect mail address from being registered.

A communication control part 108 transmits an address information confirmation request for confirming whether address specified in the address information inputted by an operation part 101 exists or not to a first mail server 20a. The communication control part 108 receives answer information to the previously transmitted address information confirmation request from the first mail server 20a. An address information inquiry part 109 determines based on the answer information received by the communication control part 108 whether the address information exists or not. When the address information inquiry part 109 determines that the received answer information exists in the address information, an address information control part 102 registers the address information in an address information storage part 106.