PURPOSE: To increase photographing speed to twice and to process the projection of an image or a text for a half time.

CONSTITUTION: In this method and this device; a stage for irradiating photosensitive material 1 is performed inside a housing 2 which is shielded from light, the photosensitive material 1 on a circular-arc shaped surface 3 is at the same distance with reference to a center vertical axial line 4, and a laser device generates a laser beam, then the photosensitive material 1 is irradiated with the laser beam 10 whose direction is changed by a rotary mirror as a light spot in the form of a dotted signal. The direction of the light beam 10 transmitted to be axially parallel from a collimator 8 is changed by at least two mirror surfaces provided to form an angle to the line 4, and the reflected parallel light beam 10 is converged by a lens 13 and circularly projected to the converged surface 14 of the surface 1a of the photosensitive material while it is rotated.