The present invention makes it possible to prevent substantial reduction of flow rate control accuracy in a small flow quantity range, to achieve an accurate flow rate control over the entire range of a flow rate control, and also to allow control of a wide pressure range of a chamber with an accurate flow rate control. Namely, with a gas supply facility having a plurality of pressure type flow controllers connected in parallel and a controller to control operation of pressure type flow controllers to supply a desired gas exhausted by a vacuum pump to a chamber while controlling its flow rate, one pressure type flow controller is made to be a controller to control a gas flow rate range up to 10% of the maximum flow rate to be supplied to a chamber, while the remaining pressure type flow controllers are made to be ones to control the rest of the gas flow rate range.