object side surface in the first lens unit l 1 light rays passing through a peripheral portion which is a high portion from the optical axis of the zoom lens include marginal rays which are axial rays at the telephoto end and off axis rays at the middle zoom position slightly closer to the telephoto end from the wide angle end the amount of aberrations generated in the lens is larger for light rays at a high position from the optical axis thus the lens is preferably formed to have a shape advantageous for the marginal rays and the off axis rays in view of aberration correction the axial rays at the telephoto end are substantially parallel to the optical axis thus in view of spherical aberration correction at the telephoto end curvatures of lens surfaces of the first lens unit li are preferably weak on the other hand the off axis rays at the middle zoom position enter the first lens unit l 1 at a large incident angle with respect to the optical axis thus forming each lens element of the first lens unit l 1 into a meniscus shape can reduce the incident angle of the off axis rays to the first lens unit l 1 this lens configuration is advantages for correcting aberrations for the off axis rays especially astigmatism thus the meniscus shape of the lens elements of the first lens unit l 1.