PURPOSE: To reduce a step of manual operation remarkably, by enabling composing exposure to the same raw photosensitive material to be carried out at high speed.

CONSTITUTION: A guide 3 for right and left movement and a guide 4 for vertical movement, a masking mechanism consisting of masks A, B, and a cover 18 are installed on a support plate 1 fixed. An exposure support plate 5 movable along the horizontal and vertical guides 3, 4; a support pole 2 erected on and fixed to the plate 1; an exposure head holder 7 movable vertically along the guide 4 of the pole 2; an exposure head 8 horizontally movable with respect to the exposure support plate 5 and fixed to the hlder 7; an original frame 25 for setting the original to be used for exposure; and an original support 23 for placing this frame 25 are installed.