PURPOSE: To provide the outside circumferential part of a photosensitive material with a white frame when an image on a negative film is printed and exposed on the photesensitive material.

CONSTITUTION: A toothed belt 120 is wound round between the pulley 116 of a rotary shaft 112 and the pulley 118 of a rotary shaft 114. Then, power is transmitted to the shaft 112 from a motor 146. Besides, guide shafts 122 and 123 are fitted to a frame body 102 so as to be extended in parallel with the belt 120. A mask material 124 is fitted to the guide shaft 122 through a sleeve 126 and a mask material 134 is fitted to the guide shaft 123 through a sleeve 136. Therefore, when the belt 120 is rotated by driving the rotation of the motor 146, the mask materials 124 and 134 are moved back and forth and the position of the void part is changed. Besides, mask materials 184 and 194 are also similarly moved back and forth.