To provide a zoom lens made very compact, capable of obtaining a wide viewing angle and having high performance and sufficient resolving power.

The zoom lens is constituted by arranging a first group optical system G1 having negative power, a second group optical system G2 having positive power and a third group optical system G3 having positive power successively from an object side, and is provided with a diaphragm FA integrally moving to the object side of the optical system G2. In the case of varying power from a short focal end to a long focal end, the optical systems G1, G2 and G3 are moved so that space between the optical systems G1 and G2 may be smaller and smaller and space between the optical systems G2 and G3 may be larger and larger. The optical system G2 consists of four lenses of three groups, where a positive lens E4, a negative meniscus lens E5, a positive meniscus lens E6 bonded to the negative meniscus lens E5, and a positive lens E7 are arrayed successively from the object side. Assuming that the refractive index of the negative meniscus lens E5 is N22 and the refractive index of the positive meniscus lens E6 is N23, they satisfy 0.15(N22-N23)0.40.