PURPOSE: To make it possible to surely carry out a predetermined paper feed in a paper feed means provided therein with a plurality of paper feed ports, by setting a priority paper feed port among them so that thus set priority paper feed port is surely selected even in an automatic paper selecting mode.

CONSTITUTION: Priority paper feed port set keys 503, 504 which are switches for designating a priority paper feed port, designate a priority paper feed port which has been set when a power source is turned on. In such a case that no priority paper feed port has been set when the power source is turned on, if it is determined that a first paper feed port is selected when a paper selecting switch is turned on, a second paper feed port is selected and the paper size code thereof is inputted. If paper runs out during copying operation with the use of an automatic paper feed cassette 20 through the first paper feed port, it is judged whether the size of paper in an automatic paper feed cassette 20 through the second paper feed port is suitable or not, and if it is suitable, copying operation is continued.