Patent ID: 7733471

Claim:
A foreign substance inspection apparatus comprising: an irradiating unit configured to emit irradiating light to be obliquely incident on a surface to be inspected to form a linear irradiation region on the surface to be inspected; and first and second detecting units arranged on a same side as that provided with the irradiating unit with respect to the surface to be inspected, the first and second detecting units configured to detect scattered light caused by a foreign substance on the surface to be inspected, wherein the first and second detecting units are arranged at opposite positions with respect to a plane containing the linear irradiation region, wherein the irradiating unit emits linearly polarized light as the irradiating light to be incident on the surface to be inspected, wherein the irradiating unit has a changing part configured to change a polarization direction of the linearly polarized light to be incident on the surface to be inspected, wherein the first and second detecting units are selectively used so that one is used at a time, and wherein the changing part changes the polarization direction of the linearly polarized light in accordance with the detecting unit that is used.