Imaging lens

An imaging lens comprising:

• a first lens having positive refractive power;
• a second lens;
• a third lens;
• a fourth lens having negative refractive power;
• a fifth lens;
• and
• a sixth lens having negative refractive power, arranged in this order from an object side to an image plane side,
• wherein said first lens is formed in a shape so that a paraxial curvature radius of a surface thereof on the object side is positive near an optical axis thereof,
• said second lens is formed in a shape so that a paraxial curvature radius of a surface thereof on the image plane side is positive near an optical axis thereof,
• said sixth lens is formed in a shape so that a surface thereof on the object side and a surface thereof on the image plane side are aspherical,
• said sixth lens is formed in the shape so that a paraxial curvature radius of the surface thereof on the image plane side is negative near an optical axis thereof, and
• said sixth lens is formed in the shape so that the surface thereof on the object side has a paraxial curvature radius R6f and the surface thereof on the image plane side has a paraxial curvature radius R6r, said first lens is arranged so that the surface thereof on the object side is away from an image plane by a distance La on the optical axis thereof, said imaging lens has an angle of view 2ω, and said fourth lens is arranged to be away from the fifth lens by a distance D45 on an optical axis thereof so that the following conditional expressions are satisfied:
• 3<|R6r/R6f|<150,
• 1.2<La/Hmax<1.8,
• 70°≤2ω,
• 0.05<D45/f<0.5,
• where Hmax is a maximum image height of the image plane and f is a focal length of a whole lens system.