1. A photomask inspecting method for inspecting a photomask having a design pattern and a dummy pattern, formed on the basis of photomask data designating a photomask, said photomask inspecting method comprising the steps of: preparing defect-discriminating data for discriminating between defects in a design pattern area and those in a dummy pattern area; inspecting the photomask on the basis of the photomask pattern data designating a photomask, detecting a plurality of defects, and determining coordinates indicating the positions of the defects; discriminating between the defects in the design pattern area and those in the dummy pattern area on the basis of the positions of the defects indicated by coordinates and the defect-discriminating data; and examining the defects in the design pattern area and those in the dummy pattern area on the basis of predetermined inspection specifications corresponding to the defects in the respective areas.