Defect inspection apparatus

A defect inspection apparatus for inspecting a defect on an object to be inspected by radiating a light beam onto the object to be inspected, and receiving scattered light which is generated from the defect upon radiation of the light beam, comprising:

• a light source for emitting the light beam;
• light beam expansion means for expanding the light beam in a predetermined direction, and radiating the expanded light beam onto the object to be inspected;
• scanning means for scanning the object to be inspected relative to the light beam to be radiated onto the object to be inspected in a direction crossing the expansion direction of the light beam;
• light-receiving means for photoelectrically converting the scattered light generated from the defect on the object to be inspected;
• and
• light-shielding means having a plurality of edges for limiting the light beam expanded by said light beam expansion means at two end portions, in the expansion direction, of the light beam, at least one of said plurality of edges being formed to be transverse to the scanning direction.