A facsimile device, which can switch a transmission method between an electronic-mail transmission method and a real-time transmission method for each transmission, is provided. The facsimile device includes an electronic-mail control unit used for transmitting image information in an electronic-mail format to a destination through a computer network, a real-time network control unit used for transmitting the image information to the destination while the facsimile device and the destination are connected on line through the computer network, and a transmission specifying unit specifying one of the electronic-mail control unit and the real-time network control unit as a communication control unit in accordance with a destination address of the destination. The facsimile device transmits the image information to the destination address by use of the communication control unit specified by a user through the transmission specifying unit.