PURPOSE: To aim at compactness and light weight while maintaining flow control accuracy by providing the inside of a volume part with polymeric gel deformed by electric or thermal responsivenss to deform an elastic film elastically so as to adjust the area of a fluid passage.

CONSTITUTION: In the state of not imparting DC electric field to polymeric gel 5, the polymeric gel 5 is contracted, and a needle 25 opens a fluid outlet 21. When DC electric field is imparted, the polymeric gel 5 swells and closes the fluid outlet 21. The swelling quantity of the polymeric gel 5 is gradually changed by the gradual change of voltage applied to the polymeric gel 5 so as to enable the outflow quantity adjustment of a fluid by the needle 25. Such a fluid control device is compact and lightweight because of not using mechanical transmission mechanism. In addition, since the polymeric gel 5 is correct in movement to the value of DC electric field, the action of the needle 25 is correct so as to make flow control accuracy sufficient.