An imaging lens includes a first lens having at least one aspheric surface; a second lens having at least one aspheric surface; a third lens having at least one aspheric surface; a fourth lens having at least one aspheric surface; a fifth lens having at least one aspheric surface; a sixth lens having two aspheric surfaces; and a seventh lens having two aspheric surfaces, arranged in this order from an object side to an image plane side respectively with a space in between. The imaging lens has a total of seven lenses. The first lens is formed in a shape so that a surface on the object side is convex near an optical axis. The seventh lens is formed in a shape so that a surface on the image plane side is concave near the optical axis. The fifth lens and the sixth lens have specific Abbe's numbers.