To acquire information to trace a person who is going to copy a prescribed original or has copied the prescribed original by recognizing a prescribed pattern included in a picture obtained by a picture read means and photographing a scene in the vicinity of the subject image forming device depending on the recognition result of a recognition means.

When an image processing section 2 discriminates that a copy object is a prescribed original, a control section 3 operates a camera 4 that can electrically photographs a picture or a video image and allows a memory 5 to record a picture photographed by the camera 4. In the case of recording the photographed picture in the memory 5, the control section 3 records information denoting its photographing date and time to the memory 5 together with the photographed picture. In the case that the received picture is discriminated to be in matching with or similar to the picture of a prescribed original, the image processing section 2 reduces the received picture or segments a picture area in matching with or similar to a characteristic pattern to the prescribed original from the input picture and gives the segmented picture to the control section 3. Thus, on the occurrence of falsification, clue to investigation can be left.