1. A region-of-interest determination apparatus comprising: a calculation unit which calculates the incidence of a defect based on at least a plurality of kinds of defect attribute information regarding defect data, the defect data including an image corresponding to a defect position detected on a specimen by inspection thereof or an image corresponding to a defect position predicted to be likely to develop a defect on the specimen, both images being obtained by imaging; and a region determination unit which extracts the defect data of which said incidence is higher than a predetermined level, and determines the region to be observed or inspected on the specimen based on the extracted defect data.