IMAGING LENS

PROBLEM TO BE SOLVED: To provide an imaging lens having a four-lens configuration, in which various aberrations are excellently corrected regardless of a large diameter.SOLUTION: An imaging lens LN comprises, in order from an object side, a negative first lens L1 concave to the object side, a positive second lens L2, a diaphragm ST, a biconvex positive third lens L3, and a negative fourth lens L4 cemented to the third lens L3 and satisfies a conditional expression of nd2-nd1>0.1 (nd1 is the refractive index of the first lens L1 and nd2 is the refractive index of the second lens L2).