An imaging lens module includes a fixed aperture stop and an optical module, and the optical module includes a first, a second, a third and a fourth lenses. The first lens has a meniscus lens with positive refractive power and a concave surface disposed towards the image. The second lens has a meniscus lens with negative refractive power and a concave surface disposed towards the image. The third lens has a meniscus lens with positive refractive power and a convex surface disposed towards the image. The fourth lens has a concave surface disposed towards the object.