To provide a wide-angle lens equipped with a gradient index lens which has the high performance to make the lens usable for a camera for an electronic image, a camera for a film, etc., and makes good imaging performance obtainable even in a region of a relatively wide angle of view (≥80°).

The wide-angle lens has a photographing angle of view of ≥80° and is equipped, successively from an object side, with a first lens group G1 having positive refractive power, an aperture-stop S, and a second lens group G2 having positive refractive power. The first lens group G1 includes a negative meniscus lens L2 which is the graded index lens GRIN of the refractive index changing continuously in an optical axis direction and a lens L5 having an aspherical surface ASP. The second lens group G2 includes at least cemented lenses (L11 and L12, L13 and L14, and L15 and L16). Equation 1.5<bf/f<5.0 is satisfied when the focal length of the entire lens system is defined as f and the back focus thereof as bf.