The present invention is an imaging lens of which optical performance does not deteriorate even in a high temperature environment, various aberrations are well corrected, optical length is short, and back focus is sufficiently secured, the imaging lens comprising a first lens 14, an aperture stop S, a second lens 16, and a third lens 18, which are arranged in this sequence from an object side to an image side. For the first lens, a single lens is used. The second lens comprises a first sub-lens L1, a second sub-lens L2 and a third sub-lens L3, arranged in this sequence from the object side to the image side. The third lens comprises a fourth sub-lens L4, a fifth sub-lens L5 and a sixth sub-lens L6, arranged in this sequence from the object side to the image side. The first lens is formed of a transparent curable silicone resin, and the first, third, fourth and sixth sub-lenses are also formed of the transparent curable silicone resin. The second sub-lens and the fifth sub-lens are formed of a high softening temperature glass material.