Imaging lens

1. An imaging lens consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,

wherein Abbe numbers of materials of the first lens, the second lens, the fourth lens and the sixth lens for d-line are greater than or equal to 40,

wherein when the Abbe number of the material of the first lens for d-line is νd 1 , and the Abbe number of the material of the third lens for d-line is νd 3 , νd 1 /νd 3 is greater than or equal to 1.4 and less than or equal to 2.5, and

wherein the following conditional formulas are satisfied:

−0.11<( R 8 +R 9)/( R 8 −R 9)   (1-1);

( R 10 +R 11)/( R 10 −R 11)<−0.35   (4-1);

1.9<( D 4 +D 5)/ f< 4.4   (19-3);

−0.2 <f/R 5<0.2   (20-3);

−2.0 <f/R 3<1.5   (21-2); and

2 <f 45 /f< 25   (23), where

R 8 : a curvature radius of an object-side surface of fourth lens,

R 9 : a curvature radius of an image-side surface of fourth lens,

R 10 : a curvature radius of an object-side surface of fifth lens, R 11 : a curvature radius of an image-side surface of fifth lens,

D 4 : an air space between the second lens and the third lens on an optical axis,

D 5 : a center thickness of the third lens,

f: a focal length of an entire system,

R 5 : a curvature radius of an object-side surface of the third lens,

R 3 : a curvature radius of an object-side surface of the second lens, and

f 45 : a combined focal length of the fourth lens and the fifth lens.

2. The imaging lens, as defined in claim 1 , where a stop is arranged between the third lens and the fourth lens.