PURPOSE: To prevent a magazine from erroneous loading due to inability to discriminate a discrimination mark by providing the two discrimination marks in the vicinity of the final end of a recording material, measuring its drawn out length in the point of time of detecting the first discrimination mark, and controlling a draw out means and a cutting means in accordance with a measuring result of the drawn out length.

CONSTITUTION: In an image forming device, a sensitive material 15 stored in a sensitive material magazine 13 is successively drawn out by paired conveying rollers 39, and the material 15, after cut into a predetermined length by a cutter 17, is conveyed to a side of an exposure part 19. Two discrimination marks with a predetermined length apart in the lengthwise direction in the vicinity of a final end of the sensitive material 15 are provided. When the first discrimination mark is detected by a sensor, a drawn out length L in the point of time of this detection is compared with a rated length SL, to immediately cut the material, in the case of a relation where L=SL, and on the other hand, to draw out the first discrimination mark to a cutter position in the case of a relation where L<SL. When the drawn out length L in this point of time is conveyable length ML or more, the material is immediately cut, and on the other hand when a relation is L<ML, cut by drawing out the second discrimination mark to the cutter position.