Abstract: A defect inspecting apparatus for determining the presence of a defect element adhering to either of the front and back surfaces of a thin film-like object to be inspected (the object having a light-transmitting property) applies two light beams of different wavelengths to a surface of the object and varies the incident angle of the light beams. A first photoelectric detector receives light of the two light beams reflected by or transmitted by the object, and a second photoelectric detector receives light of the two light beams scattered by the defect element. A discriminator determines the surface of the object to which the defect element adheres based on detection outputs of the photoelectric detectors.