In a method of inspecting defects, a first actual region of an actual object is inspected based on a first characteristic parameter as an inspection condition. A point where an inspection region of the actual object is changed into a second actual region from the first actual region is determined. The second actual region is then inspected based on a second characteristic parameter as the inspection condition. The first and second parameters may include contrast of a light that is reflected from a reference object, intensity of the light, brightness of the light, a size of a minute structure on the reference object, etc. The characteristic parameters of each reference region on the reference object are set. Thus, the defects may be accurately classified so that a time and a cost for reviewing the defects may be markedly reduced.