To realize a color image reading lens constituted of a small number of lenses, that is, five lenses of four groups, which is bright, where the curvature of field is satisfactorily corrected with aperture efficiency near to 100% to a periphery part, and which has high contrast to the outermost periphery from the vicinity of an optical axis in a high spatial frequency area, whose axial chromatic aberration and also secondary spectrum by the axial chromatic aberration are satisfactorily corrected and which can cope with the read of a full color image.

The color image reading lens is constituted of five lenses of four groups, that is, three positive lenses and two negative lenses, where a 1st group I to a 4th group IV being positive, negative, negative and positive lenses are arranged from an object side, and which has a diaphragm S between the 2nd and the 3rd groups, and is constituted so that partial dispersion deviation: δθgd being deviation from a reference line of partial dispersion: θgd of the material of the lens may be positive on one or more positive lenses on a coordinate plane where the partial dispersion: θgd and Abbe number: νd are set as orthogonal two axes.