PURPOSE: To minimize the reduction rate of an original image even in the case of an original of various sizes by allowing a synthesis means to conduct no processing when the size of an original is within a half of the size of a form to be outputted and to implement rotation or reduction when the size of the original exceeds a half of the size of the form to be outputted.

CONSTITUTION: This copying machine is provided with an image synthesis mode selection means 2 to read two originals twice from a platen and to copy them onto one form. A write means 4 to a storage means gives information of 90° rotation when the original size is a half of an output form through 90° rotation, and of reducing the image of the original till the image reaches a half size of the output form in other cases to a synthesis means 5 when the image synthesis mode is selected. As a result, since an image synthesized on one page is written in the synthesis means 5 at a minimum reduction rate, after the image of the two originals are synthesized, a print means 6 outputs a resulting images automatically.