An original scanning device can set a brake operation starting timing in a scanner backward movement to a predetermined timing, even if a scanning distance of the device is determined at any distance. To do so, a copy machine starts braking the scanning device when a sensor detects that the scanning device backwardly moved to a predetermined position. In this machine, a distance to be scanned by the scanning device is determined based on an original size or a copy magnification, it is judged whether or not a distance between a turn position of the scanning device and the predetermined position according to the determined distance to be scanned is a distance by which the scanning device can reach a predetermined speed in its backward movement, the scanning device is backwardly moved after forwardly moving it to a position according to the determined distance to be scanned in case of affirmative judgment, and the scanning device is backwardly moved after forwardly moving it to a position according to the distance by which the scanning device can reach the predetermined speed in its backward movement in case of negative judgment.