1. A semiconductor inspecting system comprising: a first memory for storing therein a design data of a semiconductor device; a data retrieving part for extracting an inspected object region from said first memory, said inspected object region being a region serving as an object to be inspected; a design characteristic item data preparing part for deriving numerical values indicative of design characteristics of said design data every one of lattice regions which are obtained by dividing said inspected object region extracted by said data retrieving part into lattices of an optional size and for preparing a design characteristic item data; a characteristic classification preparing part for classifying said design characteristic item data into a desired number of groups to prepare a characteristic classification data; a sampling part extracting said lattice regions at random from said characteristic classification data at a certain sampling rate with respect to the number of said lattice regions belonging to said groups; a second memory for storing therein a defect inspection data which is a data concerning a defect obtained by inspection with respect to a pattern of said lattice regions extracted at said sampling rate from processed patterns which are processed on the basis of said design data; and an operation part for calculating the number of defects in the whole inspected object region on the basis of said defect inspection data, said character classification data and said sampling rate.