To measure defect shapes of a lens, and to conduct itemization for defects of the lens, with simple constitution.

A variation computing means 6 retrieves image data of an inspected lens 1 in an image data storing means 4 from three directions which are longitudinal, lateral and diagonal directions to determine the average value of sequential values as an operation predicted value, and an absolute value difference between the value, and an observed value is computed to be determined as a variation. A defect detecting means 13 computes whether or not the variation computed by the computing means 6 is larger than the value set by a threshold setting means, so as to detect the presence of a defect. A defect area computing means conducts labeling processing for defect position information stored in a defect position-storing means 16 to compute the number and respective areas of respective defects. A defect-full-length measuring means 10 measures the entire length of the defect based on the defect position information and the area of the defect. A defect itemizing means 14 itemizes the defects based on the areas of the defects and their entire lengths in respective threshold. A quality determining means 15 determines the quality of the lens 1 by confirming wether the areas, the entire lengths and the number exceed predetermined specified values.