The control section of a PDA incorporating a radio communication function adds respective subaddresses as identifiers to the mail address allocated to one account. The subaddresses classify the mail address as a plurality of destinations. The control section transmits an electronic mail to which one of the subaddresses is added to a mail server. The control section also discriminates the subaddress added as an identifier to an electronic mail by accessing a mailbox in the mail server, and receives the electronic mail to which the subaddress is added.