An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is aspheric. The first lens and the second lens have a specific composite focal length. The third lens have a specific focal length. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.