PURPOSE: To make the directions of the back face and surface of copied objects coincide even if the stapling side of documents and the stapling side of sheets differ and make the directions of the back face and surface of the copied objects coincide on the image after compilation when the double-side documents are copied on both faces by a copying machine.

CONSTITUTION: (a) The stapling side of documents and the stapling side of sheets are fed to a controller when double-face documents are copied on both faces, and the rotation angle of an image is decided. (b) The length in the main scanning direction is compared with the length in the auxiliary scanning direction in an image memory, and the rotation angle of the image is decided based on the compared result.