In a foreign particle inspecting method and apparatus in which a polarized beam is applied to a surface to be inspected through a light transmitting member mounted thereon, in which scattered light from a foreign particle on the surface to be inspected is received by a light receiving device through the light transmitting member, and in which the foreign particle is discriminated based on a detection signal from the light receiving device, the detection signal is corrected in conformity with the transmittance of the light transmitting member for polarized incident scanning light and the transmittance of the light transmitting member for non-polarized light scattered from the foreign particle, for various angles of incidence of the polarized light and emergence of the non-polarized light. Foreign particle data may be indicated by a mapping method.