Collective transmission of image data for a same destination, containing one-side and two-side originals in mixed manner is enabled without deteriorating the interchangeability of a facsimile communication.A one-touch dial memory is rendered capable of storing timer transmission data, and, when the memory transmission is designated by a one-touch key of an operation unit, two-side and one-side images are read and are stored in an image memory. When the image data of plural sets are to be transmitted to the same destination at a designated time, such image data of plural sets are collectively transmitted to the same destination by separately connecting the calling between the set of the two-side images and that of the one-side images.