A lens array of an erecting mode with unity amplification which scarcely generates a stray light and a flare light, is provided. In the lens array of the erecting mode with unity amplification constituted by superposing a plurality of lens plates in which convex lenses are arrayed and formed on both sides, a lens pitch P of the array direction of the convex lenses is not less than two times the height of an inverted image formed inside the lens array of the erecting mode with unity amplification, and an aperture diaphragm is provided on individual lens elements in a position in which the inverted image is formed so that a light does not pass through the outside of the region of a circle having the height of the inverted image as a radius.