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, comprising an aperture stop S and a junction type compound lens 14 having a positive refractive power, wherein the aperture stop and the junction type compound lens are arranged in this sequence from an object side to an image side. The junction type compound lens comprises a first lens L1, a second lens L2 and a third lens L3 arranged in this sequence from the object side to the image side. The first lens and the third lens are formed of a curable resin material, and the second lens is formed of an optical glass. The first lens and the second lens are directly bonded, and the second lens and the third lens are directly bonded. The object side face of the first lens and the image side face of the third lens are aspherical.