1. A defect pattern evaluation method, comprising: performing optical defect inspection on a pattern on a substrate after a predetermined process for manufacturing a semiconductor device; detecting defects by the optical defect inspection; classifying the defects according to a type of a pattern layout using a pattern layout corresponding to coordinates of the defects; calculating using a computer a defect occurrence rate by dividing the number of defects of each pattern layout by an arrangement number of the pattern layouts in an inspection region through a computer; and outputting the defect occurrence rate of each pattern layout as an evaluation result.