Abstract: A surface inspection apparatus of the present invention comprises an optical sensor having a plurality of detecting portions arranged in a sub-scan direction, the detecting portions being responsive to the scattering light for producing the detection signals correspondingly to respective pixels, a detection optical system including an objective lens and disposed between the optical sensor and the thing to be inspected, a projection optical system for irradiating the thing to be inspected with the laser beam having a cross sectional area large enough to cover the scattering light to be received by the plurality of the detecting portions through the detection optical system and an inspection device responsive to the detection signals for inspecting the surface of the thing to be inspected, wherein one of the detection optical system lens and the optical sensor is mounted such that a setting axis thereof is aligned in a plane perpendicular to an optical axis of the detection optical system lens with a light rece

Abstract: In the present invention, an extraneous substance inspection optical system having an extraneous inspection area of a predetermined scanning width in subscanning direction of a matter to be inspected is positioned in such a manner that the extraneous substance inspection area at a moment when the matter to be inspected is started to move in main scanning direction is arranged at a position in the main scanning direction corresponding to a head portion of the matter to be inspected; the matter to be inspected is moved in the main scanning direction to be subjected to a forward scanning for the matter to be inspected to thereby detect possible extraneous substances in the extraneous inspection area; and the matter to be inspected is rotated by 180.degree.