An imaging lens includes: a first lens having a convex surface facing the object side, and having a positive refractive power; a second lens being a meniscus lens having a negative refractive power; a third lens having a concave surface facing the imaging side; a fourth lens being a meniscus lens having a positive refractive power, having a convex surface facing the image side; a fifth lens having a negative refractive power, having a concave surface facing the image side on an optical axis, the surface facing the image side having an inflection point outside the optical axis; a sixth lens having a rear surface facing the image side and a front surface facing the object side, the rear surface being aspherical with a inflection point outside an optical axis, the front surface having a curvature less than other lenses' curvatures, the sixth lens serving as an infrared cut-off filter.