PURPOSE: To obtain a compact, bright wide-angle zoom lens with high performance by arranging a lens which varies in refractive index in the optical-axis direction in the image-side positive lens group of a rear group.

CONSTITUTION: A front group which has negative refracting power consists of a positive, a negative, a negative, a positive, a negative, and a positive lens from the object side and the rear group which has positive refracting power consists of a positive lens group composed of a cemented positive lens of a positive and a negative lens, a positive lens, and a positive lens convex on the object side to a small radius of curvature from, a negative lens group composed of a negative lens concave on the image side to a small radius of curvature, and a positive lens group composed of a positive cemented lens of a negative and a positive lens and a positive lens from the object side. The positive lens closest to the image side is a lens which varies in refractive index in the optical-axis direction. Consequently, the compact, extremely bright zoom lens which has high performance is obtained.