An optical scanning lens which is used in a scanning and age forming
optical system which gathers a light flux deflected by a light deflector
in the vicinity of a surface to be scanned. The lens is formed by plastic
molding of polyolefin resin, and the following condition is satisfied:
0<.vertline..DELTA.n(x)-min[.DELTA.n(x)].vertline.<34.times.10.sup.
-5, where .DELTA.n(x) denotes a refractive-index distribution existing
inside the lens, in a range which the light flux passes through, in the
lens, and min[.DELTA.n(x)] denotes the minimum value of the .DELTA.n(x).
