An exposure apparatus in which a photographic light-sensitive material is exposed to a light image of an original, includes: a light illuminating member for illuminating a light to the original; an optical member for projecting a light transmitted through or reflected on the illuminated original onto an exposure position as a line image of the original; a material conveyor for conveying the material at a constant speed while the line image of the original is projected onto the material; a moving member for moving the original at a definite speed while the line image of the original is projected onto the material; and a start position determining member for determining a start position of the original at which the moving member starts moving according to magnification of the projected image of the original or image density of the original. The moving member starts moving the original from the start position, thereby the definite speed of the original while the slit image of the original is projected onto the material, is varied.