A zoom lens of variable power ratio of the order of 3 in which the whole of the zoom lens is made up of three lens elements groups and the power configuration of each of the groups has an arrangement of negative, positive, and negative. The zoom lens includes, sequentially from an object side thereof, a first lens elements group which has a negative refraction power as a whole, a second lens elements group which has a positive refraction power as a whole, and a third lens element group, which has a negative refraction power as a whole. A variable power is realized by shifting the positions of the first and second lens elements group in the direction of an optical axis thereof.