PURPOSE: To realize such a penetration type that an original is irradiated with light from above, by driving and moving the 1st movable reflecting mirror and the 1st light source synchronously at the same speed.

CONSTITUTION: The 2nd movable mirrors 6 and 7 are coupled together mechanically to move in the same direction with a movable mirror 5 at a speed a half the moving speed of the movable mirror 5, so the distance from the original 4 to a lens 11 is adjusted to double as long as the focal distance of the lens 11 during the movement of the 1st movable mirror 5 from the left end to the right end of the original 4. Therefore, the unmagnification light image of the picture on the original 4 in mirror image relation is projected on the surface of a photosensitive drum 2. A motor driving a scanning pulley 19 to move the 1st movable mirror 5 and the 1st light source 14 in corresponding relation and a driving motor 34 for moving the 1st light source 14 are driven synchronously and the 1st movable mirror and the 1st light source move at the same speed, so the light from the light source never passes through the original by irradiation and reflection and passes through it only by irradiation, so light attenuation is less.