A flow rate control device, including: a body including first and second ports for supplying and discharging pressurized fluid; a set of first and second solenoid valves connected to an upper part of the body and selecting a state of flow of the pressurized fluid; and an opening/closing valve for increasing a flow rate of the pressurized fluid which flows as the result of selection by the first and second solenoid valves. The pressurized fluid is caused to flow from the first port to the second port at a predetermined flow rate while the opening/closing valve is closed, and then the flow rate of the pressurized fluid flowing from the first port to the second port is increased by opening the opening/closing valve.