In a defect inspection system using a plurality of detectors such as an upright detector and an oblique detector, if illumination light and wafer height are adjusted to the detection field of view of one detector, a defocused image is detected by other remaining detectors, resulting in degradation of the detection sensitivity. The present invention solves this problem.When a plurality of detectors such as an upright detector and an oblique detector are used in the defect inspection system, the reduction of the inspection sensitivity can be prevented by correcting the field positions of the other remaining detectors with respect to the field of view of the one detector. Further, the variation in optical axis for each inspection system due to the variation in parts and assembly errors can be reduced.