There is provided a technique that is capable of attracting a sample without making the voltage applied to an electrostatic chuck unnecessarily large. Attraction experiments with respect to the electrostatic chuck are performed using a testing sample whose degree of warp and pattern of warp are known, and a critical application voltage at which the attraction state changes from “bad” to “good” is found. When measuring an inspection target sample, the flatness of the inspection target sample is measured, and the degree of warp and pattern of warp of the inspection target sample are detected. Based on the degree of warp and pattern of warp of the inspection target sample and on the known critical application voltage, the application voltage for the electrostatic chuck is set.