A substrate processing a technology including: a substrate holder; a tubular reactor that houses the substrate holder; an inlet flange connected to the tubular reactor including a plurality of gas introduction ports; a lid that closes a lower opening of the inlet flange in a manner such that the substrate holder can be carried in and out; heater elements disposed along the outer peripheral surface of the inlet flange while avoiding the gas introduction ports; temperature sensors thermally coupled to the inlet flange or any heater element and adapted to detect temperatures; and a temperature controller that divides of the heater elements into groups and controls power supply to the respective heater elements independently for each of the groups based on temperatures detection temperatures detected by the temperature sensors.