A method for manufacturing a semiconductor device, comprising determining a first processing condition to apply a predetermined processing to a base body in a reaction chamber of a semiconductor device manufacturing apparatus, processing the base body based on the determined first processing condition, measuring one or more process parameters which vary the processing capability of the process on the base body during the processing, determining a second processing condition during the processing so that the processing amount is a set value, from a reference state representing the relation between the processing capability and the process parameter, and the measured value of the process parameter measured during processing, and changing the processing condition from the first processing condition to the second processing condition during the processing, and performing the processing based on the second processing condition.