Abstract: A micropump utilizes electrically controlled interfacial tension between a mercury column and an electrolyte solution in a capillary tube, and also uses the gas pressure in a confined chamber connected to the capillary tube as the restoring pressure. Accordingly, the pump operates without generating external jitter or noise, in vertical, horizontal, or in any orientation against the gravitational force. In this manner, the flow rate of the pumped fluid can be widely and conveniently controlled. Further, the micropump is small in size and simple in construction, and needs extremely small power consumption.