Abstract: A gas dividing/supplying apparatus includes a pressure-type flow control system, a plurality of divided flow passages connected in parallel with each other and through which gas flowing from the pressure-type flow control system is divided and supplied to a process chamber, thermal-type mass flow sensors disposed in the divided flow passages, respectively, motor-operated valves disposed on a downstream side of the thermal-type mass flow sensors, respectively, and switching-type controllers that control opening and closing of the motor-operated valves, respectively, and, in the apparatus, the switching-type controllers perform switching between valve opening control for maintaining the motor-operated valves at a predetermined fixed valve opening degree based on a valve opening control command signal and divided flow control for regulating an opening degree of each of the motor-operated valves by feedback control based on a flow detection signal of the thermal-type mass flow sensor by a divided flow control com

Abstract: A pressure type flow rate control apparatus is provided wherein flow rate of fluid passing through an orifice is computed as Qc=KP1 (where K is a proportionality constant) or as Qc=KP2m (P1?P2)n (where K is a proportionality constant, m and n constants) by using orifice upstream side pressure P1 and/or orifice downstream side pressure P2. A fluid passage between the downstream side of a control valve and a fluid supply pipe of the pressure type flow rate control apparatus comprises at least 2 fluid passages in parallel, and orifices having different flow rate characteristics are provided for each of these fluid passages, wherein fluid in a small flow quantity area flows to one orifice for flow control of fluid in the small flow quantity area, while fluid in a large flow quantity area flows to the other orifice for flow control of fluid in the large flow quantity area.