PURPOSE: To easily set variable magnification, by incline-scanning the other mirror for receiving the light from one mirror for scanning in parallel against an original placing plate, setting its horizontal scanning lengh to half of one mirror, and reducing the drying force of the other mirror.

CONSTITUTION: A reflected ray from the first mirror 4 which is scanning in the horizontal direction against an original placing plate 1 is reflected by the second mirror 6 which is incline-scanning, and forms an image on a photosensitive drum 11 through a lens 8 and mirros 9, 10. The mirror 6 is constituted so that scanning length 7 in its horizontal direction is set to half of scanning length 5 of the mirror 4, and the scanning length 7 is scanned in the half ratio, within the same time as the scanning time of the mirror 4. Also, when the lens 8 and the mirrors 4, 5 have been set to a position shown by a full line, unmagnification is obtained, and when they have been set to a position shown by a two point chain line, reduction-transfer can be executed.