PURPOSE: To make accurate inspection irrespective of the shape of inspection pattern by inspecting whether any defect exists on the basis of the inspection image acquired from the inspection light of a short and a long wavelength component, and referencing the result obtained.

CONSTITUTION: The short wavelength component of the first inspection light 121 is solely taken out, and the rear surface of a mask 10 is irradiated therewith. The transmitted light is put incident to the first photographing means 150, and the attached foreign matter, etc., on the mask 10 are shielded against the light so as to generate a darkness, and there image formation takes place. This is computed for each picture element where the first inspection pattern A/D converted 171 is identical to the design pattern 175, and inspection 176 is made whether defect exists. On the other hand, only the long wavelength component of the second inspection light 130 is taken out, and therewith the surface of the mask 10 is irradiated. The reflected light thereby is put incident to the second photographing means 160, and image formation takes place where Cr film, etc., on the mask surface serves as light part, and inspection 177 is conducted whether defect exists from this second inspection pattern and the second design pattern of the differentiated image. A defect judging circuit 178 compares the first defect pattern with the second and passes judgement whether the defect is due to poor pattern formation on the mask or to attachment of any foreign matter.