but becomes convex in its peripheral region in addition the following conditions 1 and 2 are satisfied d 3 is the central thickness of the second lens element d 2 is the distance on the optical axis between the image side surface of the first lens element and the object side surface of the second lens element u03c5 1 is the abbe number of the first lens element and u03c5 2 is the abbe number of the second lens element in the imaging lens of the present invention because it has the referenced construction miniaturization is achieved the various aberrations are favorably corrected and thus the optical performance is enhanced compared with prior art imaging lenses of one piece construction by satisfying condition 1 curvature of field is suppressed and distortion is favorably corrected and by satisfying condition 2 it becomes especially easy to correct on axis chromatic aberration in the imaging lens of the present invention it is further desirable that it is constructed to satisfy the following condition 3 bf is the back focal length of the imaging lens namely the distance from the image side surface of the second lens element to the image plane by satisfying condition 3 it becomes easier to secure a sufficient space between the final lens element surface and the image plane and the curvature of field is suppressed in the imaging lens of the present invention it is desirable that the aspherical shape of the object side surface and the image side.