A low-cost imaging lens which corrects aberrations properly with a small F-value, ensures high performance with a larger number of constituent lenses and has a more low-profile design than before. The constituent lenses are arranged in the following order from an object side to an image side: a first lens having a convex object-side surface near an optical axis; a positive second lens; a negative third lens having a convex object-side surface near the optical axis; a fourth lens having at least one aspheric surface; a fifth lens as a double-sided aspheric lens; a sixth lens as a double-sided aspheric lens; and a seventh lens as a double-sided aspheric lens having a concave image-side surface near the optical axis. These constituent lenses are not joined to each other.