To reduce workload on an Internet facsimile machine on the transmission side, and to execute a retransmission processing promptly and reliably, an electronic mail server device includes a function for receiving an electronic mail, a function for transmitting the received electronic mail to the Internet facsimile machine of a destination via the Internet, and a function for carrying out a facsimile transmission of the image data via a public telephone network. The electronic mail server device also includes a RAM which stores an address/number corresponding table which corresponds the electronic mail address and the facsimile number of the Internet facsimile machine of the destination. When receiving the electronic mail including the image data, and failing to transmit the electronic mail including the image data to the Internet facsimile machine of the destination, a main control unit carries out a facsimile transmission of the image data of the electronic mail to the Internet facsimile machine of the destination via the public telephone network in accordance with the facsimile number corresponding to the electronic mail address of the Internet facsimile machine of the destination.