To ensure a stable changeover control of a plurality of flow control valves, a highly accurate following control to a wide range of varied target value, and a stable control even in the case of disturbance.

A flow control device is provided to followingly control the flow of fluid flowing in a system to a varied target value (Ms) by controlling a plurality of flow control valves. In this device, the plurality of flow control valves are controlled by feed-forward control means 1-4. The present flow (m) of fluid controlled by the control operation is compared with the value (Ms) to obtain a deviation (s(t)). According to the deviation, it is determined whether PI control is executed or not. Then, according to the result of detection, a PI control signal is added to a control signal in the feed-forward control means to have a synthesized operation amount.