Abstract: A copying machine having the APS mode for automatically selecting size of copy paper based on the size of the original and the copying magnification includes an APS mode setting switch, copy paper selecting switch for manually selecting the size of the copy paper and a controller for controlling the copying machine such that the operation of the copy paper selecting switch is inhibited when the APS mode is set. When the APS mode is set in the copying machine, the copy paper having the size selected by the copy paper selecting switch is inhibited even if the user operates the copy paper selection switch, due to the operation of the controller.