PURPOSE: To increase the density of housing waste sheets into a housing box by cutting the waste sheets in the housing box by means of a cutter to the length shorter than the length at which the sheets are plaited on each other and longer than the min. conveyable length of an image recorder.

CONSTITUTION: The photosensitive material S conveyed from a stripping device 9 turns on a sensor switch SW1 and is pinched by conveyance rollers 102 and is further pinched by discharge rollers 104; thereafter the material is cut by a rotary cutter 106 in a cutter unit 100 disposed between the rollers 102 and the rollers 104. The cut material is discarded into the photosensitive material housing box 110. The cutting length to be set at this time is determined to about the length at which the waste photosensitive material is folded and is not inclined in the housing box 110 in accordance with the stiffness of the base material used for the photosensitive material S and the length of the base of the housing box 110 in the advance direction of the waste photosensitive material. The spacing between the waste materials is thereby decreased and the housing density of the photosensitive materials is increased.