PURPOSE: To make an automatic negative/positive decision on a transparent document and to eliminate miscopying by providing a means which decides the negative/positive decision according to the light measured value of a photometry sensor for the transparent document.

CONSTITUTION: The photometry sensor 43 is provided at, for example, an image formation position in an optical path which is formed when the shutter 44 of an exposure part 14 is closed, and the photometric value of the photometry sensor 43 is inputted to a decision means such as a microcomputer to make the negative/positive decision. When an exposure quantity control system is selected, the relation between transmission density and the exposure quantity is found experimentally in advance and stored in an exposure quantity control means and one condition is selected among stored exposure control systems according to the negative/positive decision result. Thus, a color negative film and a color positive film are discriminated automatically, so miscopying is eliminated.