Patent ID: 7491959

Claim:
A defect inspection apparatus comprising: an illumination optical system which sets a transmission illumination region and a reflection illumination region on an inspection target surface of a mask; first and second imaging units having first and second visual fields which are set on the inspection target surface; an imaging optical system that provides images, which are present on the first and second visual fields, on the first and second imaging units; a defect detection unit which detects a defect of the mask on the basis of the images provided on the first and second imaging units; and a control unit which controls a positional relationship between setting positions of the transmission illumination region and the reflection illumination region and setting positions of the first and second visual fields, the control unit including an illumination region position control unit which controls positions of the transmission illumination region and the reflection illumination region, and a visual field position control unit which controls positions of the first and second visual fields; wherein the visual field position control unit controls the positions of the first and second visual fields to space the first and second visual fields apart from each other, and wherein the visual field position control unit executes a first position control in which a center axis of the first visual field agrees with a center axis of an objective visual field, a second position control in which a center axis of the second visual field agrees with the center axis of the objective visual field, and a third position control in which the center axis of the objective visual field lies between the center axis of the first visual field and the center axis of the second visual field.