A zoom lens having a change-magnification range ranging from wide angle to telephoto comprises, in succession from the object side, first lens group of positive refractive power movable on the optical axis, a second lens group of negative refractive power fixed relative to the image plane at a determined position, a third lens group of negative refractive power movable on the optical axis, and a fourth lens group of positive refractive power movable on the optical axis. The first and fourth lens groups are moved toward the object side in linear fashion to change magnification from the wide angle end to the telephoto end while the third lens group is moved toward the object side at the same time in non-linear fashion to keep the image plane at the determined position.