An imaging lens consisting of a first lens: a second lens; a third lens; an aperture stop; and a fourth lens, which are sequentially arranged from the object side of the imaging lens, wherein the first lens has negative power, and an object-side surface of the first lens is convex and an image-side surface of the first lens is concave, and wherein an object-side surface and an image-side surface of the second lens are aspheric, and the second lens has negative power in the vicinity of the optical axis of the imaging lens, and the object-side surface of the second lens is concave in the vicinity of the optical axis, and the image-side surface of the second lens is concave in the vicinity of the optical axis, and wherein an object-side surface and an image-side surface of the third lens are aspheric, and the third lens has positive power in the vicinity of.the optical axis of the imaging lens, and the object-side surface of the third lens is convex in the vicinity of the optical axis, and the image-side surface of the third lens is convex in the vicinity of the optical axis, and wherein an object-side surface and an image-side surface of the fourth lens are aspheric, and the fourth lens has positive power in the vicinity of the optical axis of the imaging lens, and the object-side surface of the fourth lens is concave in the vicinity of the optical axis, and the image-side surface of the fourth lens is convex in the vicinity of the optical axis, and wherein when the paraxial curvature radius of the image-side surface of the second lens is r4, and the paraxial curvature radius of the object-side surface of the third lens is r5, the following formula is satisfied: 0.0 < r 5 / r 4 < 1.0 a second lens; a third lens; an aperture stop; and a fourth lens, which are sequentially arranged from the object side of the imaging lens, wherein the first lens has negative power, and an object-side surface of the first lens is convex and an image-side surface of the first lens is concave, and wherein an object-side surface and an image-side surface of the second lens are aspheric, and the second lens has negative power in the vicinity of the optical axis of the imaging lens, and the object-side surface of the second lens is concave in the vicinity of the optical axis, and the image-side surface of the second lens is concave in the vicinity of the optical axis, and wherein an object-side surface and an image-side surface of the third lens are aspheric, and the third lens has positive power in the vicinity of.the optical axis of the imaging lens, and the object-side surface of the third lens is convex in the vicinity of the optical axis, and the image-side surface of the third lens is convex in the vicinity of the optical axis, and wherein an object-side surface and an image-side surface of the fourth lens are aspheric, and the fourth lens has positive power in the vicinity of the optical axis of the imaging lens, and the object-side surface of the fourth lens is concave in the vicinity of the optical axis, and the image-side surface of the fourth lens is convex in the vicinity of the optical axis, and wherein when the paraxial curvature radius of the image-side surface of the second lens is r4, and the paraxial curvature radius of the object-side surface of the third lens is r5, the following formula is satisfied: 0.0 < r 5 / r 4 < 1.0