To obtain high resolution, to excellently compensate various aberrations over a wide wavelength range and to lower the manufacturing cost by setting the image read lens consisting of a modified Gaussian type lens consisting of six elements so that the shapes of the respective lenses and specific conditional expressions are satisfied.

The image read lens is constituted by arranging a 1st positive meniscus lens L1, a 2nd positive meniscus lens L2, a 3rd negative meniscus lens L3 having its concave surface on the image side, a 4th negative meniscus lens L4 having its concave surface on the object side, a 5th positive lens L5, and a 6th positive lens L6 having its convex surface on the image plane side and satisfies conditional inequalities 0.37<f12/f<0.55, 0.19<R3/f<0.26, and 0.14<R6/f<0.23. Here, (f) is the composite focal length of the whole lens system, Ri is the radius of curvature of an (i)th lens surface counted from the object side, and f12 is the composite focal length of the 1st and 2nd lenses.