PURPOSE: To discriminate that all sheet films are counted by providing a backing plate to protect the sheet films disposed in a bag-shaped light shielding member and attaching magnets to the backing plate or light shielding plate.

CONSTITUTION: A platen 38 of an image recorder 30 is drawn out and a package 10 is loaded in the platen 38. Whether the film F loaded internally in the package 10 is of the type meeting the recorder 30 or not is detected from whether the magnets 28a, 28b provided to the backing paper 14 constituting the package 10 are in the positions corresponding to magnetic sensors 40a, 40b of the platen 38 or not. An operator cuts the end part 16b of the light shielding member 12 and inserts the platen 38 into the recorder 30, then the operator removes the member 12 by pulling the end part 16a. The film F is counted by a suction cup 44 when the film F is loaded into the recorder 30 by the above-mentioned operation. The magnets 28a, 28 are displaced integrally with the lower surface part 18 of the paper 14 and are detected from the sensors 40a, 40b when all the films are counted. The end of the counting of all the films F is thus detected.