PROBLEM TO BE SOLVED: To quantitatively determine defect detection sensitivity data for use in detecting a defect in a semiconductor device, using image data detected from the surface of each semiconductor device of the plurality of semiconductor devices. SOLUTION: The image data are taken in from a desired area of the surface of each semiconductor device of the plurality of semiconductor devices. Defect information on the desired area is obtained by comparing the data obtained by arithmetically processing the image data with a defect information detection sensitivity parameter in which a prescribed threshold value is set. By varying the threshold value which is set to the defect information detection sensitivity parameter, the step for obtaining the defect information is performed plural times, and a plurality of combination data are obtained, in which the threshold value is related to the defect information. A function showing the relationship between desired statistical quantity data and the defect information detection sensitivity parameter is prepared, using the plurality of combination data. On the basis of the function, the defect information detection sensitivity data for use in obtaining the defect information on the desired area in detecting the defect of the semiconductor device are determined. COPYRIGHT: (C)2004,JPO