To reduce warpage of an internal reflection element integrally formed with resin, in an optical scanner and a color image forming apparatus having the internal reflection element.

An internal reflection element integrally formed with resin has a shape in which a sub-scanning cross section is notched by at least one of the following areas: a first area that is around an intersection of extended lines of a first internal reflection surface and a second internal reflection surface; a second area that is around an intersection of extended lines of a first transmission surface and the first internal reflection surface; and a third area that is around an intersection of extended lines of the second internal reflection surface and a second transmission surface.