To provide a zoom lens reduced in length, thickness, size and cost, wherein emission angle of the outermost angle light beams at a wide angle end is made small and it is made suitable for a solid state imaging device.

The zoom lens is provided with: a first lens group I having negative refractive power; a second lens group II having positive refractive power; and a third lens group III having positive refractive power. The first lens group I has a first lens 1 having negative refractive power and a second lens 2 which has positive refractive power and has a meniscus shape whose convex surface is facing toward an object side. The second lens group II has a third lens 3 which has positive refractive power and has a curvature of the object side surface to be greater than the curvature of the image surface side surface and a fourth lens 4 which has negative refractive power and has a curvature of the surface of the image surface side to be greater than the curvature of the object side surface. The third lens group III has a fifth lens 5 having positive refractive power. All of the first lens 1 to the fifth lens 5 are formed by a plastic material.