Scanning optical system, image formation apparatus including the scanning optical system, and imaging optical system used in the scanning optical system

A scanning optical system for deflecting a light flux from a light source and scanning a target scanning surface, the scanning optical system comprising:

• a deflector for deflecting the light flux from the light source;
• and
• an imaging optical system for focusing the light flux deflected by the deflector on the target scanning surface,
• wherein the imaging optical system has at least one optical function surface on which an optical function portion including a plurality of convex portions arranged therein so as to have a serrate cross section is formed in at least part thereof and said at least one optical function surface is formed so that a width of each of the convex portions in an arrangement direction in which the convex portions are arranged is substantially equal to or larger than a width of the light flux in the arrangement direction, which enters the optical function surface.