It is to provide an imaging lens that can maintain telecentricity, sufficiently correct various aberrations, and acquire an excellent resolution, while being small and light. The imaging lens comprises, in order from an object side towards an image surface side, a first lens which is a biconvex lens, a diaphragm, a second lens which is a meniscus lens having a negative power whose convex surface faces the image surface side, and a third lens which is a meniscus lens having a positive power whose convex surface faces the object side, wherein conditions expressed by each of following expressions are to be satisfied: 0.7≦f1/fl≦1, −6≦f2/fl≦−2.8, and 3