Abstract: A processing result storage device stores data on the results of an etching apparatus having processed a product. An apparatus property storage device stores data which indicate the property of the etching apparatus as processing property data. A process stability judgment device judges the stability of a step based on the processing result data stored in the processing result storage device and the apparatus property data stored in the apparatus property storage device. When the process stability judgment device has judged the step to be stable, the processing rate automatic calculation device calculates an etching rate. On the other hand, when the process stability judgment device has judged the step to be unstable, the processing rate recalculation device calculates an etching rate, based on the results of the etching apparatus having actually etched. The processing requirement determination device determines the etching requirements from the calculated etching rate.