A copy machine including: an original reading apparatus having a front and back surface image reading sensors, being capable of setting plural original documents, feeding out one by one, and simultaneously reading both surfaces of the documents; an image forming apparatus; a post processing apparatus for stapling and/or punching; an image processing section which rotates an image; wherein, a control section controls such that: when the memory capacity for image rotation is enough, the documents are read by the front surface image reading sensor; the obtained image data is rotated; and an image is formed on the recording sheet based on the rotated image data; whereas, when the memory capacity is not enough, an indication to re-set the documents is displayed; the re-set documents are fed out to be read by the back surface image reading sensor; an image is formed based on the image data obtained; and the post processing is executed.