A communication terminal device capable of efficiently using an image memory for storing a received image when performing both-side receiving by using both-side receiving function. A main control unit makes an image memory store the received image when performing both-side receiving via a communication unit by a continuous mode. When images of two pages that are in the relationship of a front page and a back page are present in the image memory, the images of the two pages are recorded on both sides of a sheet by a recording unit, and are erased from the image memory.