DEFECT DETECTOR BY RECEIVING BRIGHT FIELD LIGHT

PURPOSE:To enable detection of a surface detect which does not generate scattering by shielding the specular reflected luminous flux from the reflecting surface perpendicular to an optical axis by a light shielding plate. CONSTITUTION:A light shielding plate 7a which shields the specular reflected luminous flux 5 from the surface of an object to be inspected perpendicular to an optical axis is provided to a filter 7 which allows transmission of laser light. Even if the surface 1a of the object to be inspected does not generate scattering owing to a slip line, etc., the deviation of the reflecting direction owing to a slight inclination of the defect surface is detected with a photodetector 6 and the surface defect which does not generate scattering is detected as well.