1. A foreign matter inspection apparatus for inspecting the existence of foreign matters on a surface of an inspected object by irradiating optical beams to the surface of said inspected object, acquiring an image signal from a reception intensity of reflected or scattered beams and comparing said image signal with an image signal acquired from an adjacent inspected object, comprising: a device for registering feature points of alignment marks formed on the surface of said inspected object; and a device for reading said alignment marks on the surface of said inspected object; wherein alignment is executed by detecting said alignment marks formed on the surface of said inspected object on the basis of said feature points.