To provide a facsimile machine that can transmit image data of an original whose size exceeds the width of the size A3 transmittable on the communication protocol without a problem with unmagnification.

The facsimile machine discriminates whether or not the width of the image data exceeds the width of the size A3 being the specified maximum size capable of being communicated on the communication protocol. When the width of the image data exceeds the A3 specified width, the facsimile machine discriminates whether or not a read page can be transmitted with the A3 extension size and unmagnification. When the page can be transmitted with unmagnification, the facsimile machine transmits the page with the A3 extension size and unmagnification. Or the facsimile machine reduces the image data entirely to have the A3 specified width and transmits the reduced image data.