PURPOSE: To enable defect examination to be performed efficiently while avoiding detection of defects in regions which do not affect transfer by performing examination through the comparison of data about a pattern subjected to image processing and classified into three or more gradations with examination data classified into three or more gradations according to transmittance.

CONSTITUTION: A pattern on the reticle of a plate 2 to be examined is exposed to light from a light source 1, and the light transmitted through the pattern of the reticle is received by a photocell 3, and after image processing is carried out at an image processing portion 4 image data is stored in an image storage portion 5. The image processing is performed while the pattern on the reticle is classified into three or more gradations for each of the transmittances of a high-transmittance portion, a halftone shading film portion and a low- transmittance portion. Therefore, an actual pattern and examination data can be compared for examination while being classified into three gradations for each transmittance, and so not only the shaded and transparent portions but also halftone portions can be detected. Therefore, the detected halftone portion and the examination data can be compared for evaluation.