In a continuous processing system, a controller of a heat treatment apparatus calculates a weight of each layer from input target film thicknesses of a phosphorous-doped polysilicon film (D-poly film) and an amorphous silicon film (a-Si film), and calculates activation energy of stacked films based on the calculated weight and activation energy. The controller prepares a stacked film model based on the calculated activation energy and a relationship of a temperature of each zone and film thicknesses of the D-poly film and the a-Si film, and calculates an optimum temperature of each zone by using the prepared stacked film model. The controller controls power controllers of heaters to set a temperature in a reaction tube to be the calculated temperature of each zone and forms stacked films on a semiconductor wafer by controlling a pressure adjusting unit, flow rate adjusting units, etc.