Abstract: An apparatus and method for inspecting a defect of a circuit pattern formed on a semiconductor wafer includes a defect classifier have a comparison shape forming section for forming a plurality of comparison shapes corresponding to an SEM image of an inspection region by deforming the shape of the circuit pattern in accordance with a plurality of shape deformation rules using design data corresponding to the circuit pattern within the inspection region and a shape similar to the SEM image of the inspection region out of the plurality of comparison shapes formed and selected as the comparison shape, and a shape comparing and classifying section for classifying the SEM image using information of the comparison shape selected in the comparison shape forming section and the inspection shape of the circuit pattern of the SEM image of the inspection region.