An imaging lens system is provided. The imaging lens system includes a first lens that includes a convex object side surface and has a positive refractive power; a second lens that includes a concave image plane side surface and has a negative refractive power; a third lens that has a positive or negative refractive power; a fourth lens that includes a convex image plane side surface and has a positive or negative refractive power; a fifth lens that includes a convex image plane side surface and has a negative refractive power; and a sixth lens that has a negative refractive power, wherein the first through sixth lenses are arranged in order from an object side to an image plane side.