An imaging lens includes a stop; a first lens; a second lens; a third lens having positive refractive power; a fourth lens; a fifth lens having positive refractive power; and a sixth lens, arranged in this order from an object side to an image plane side. The fourth lens is formed in a shape so that a surface thereof on the image plane side is convex near an optical axis thereof. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave near an optical axis thereof. The second lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side have specific curvature radii.