To provide a small micro-electromechanical valve having a good efficiency of operating energy.

A pair of supports 22 are arranged with a gap therebetween on a substrate 50. A single-crystal arched beam 24 is extended between the supports 22. An actuator member 26 is connected to the arched beam 24 and a valve plate 30 is connected to the actuator member 26. A potential difference is imparted between the supports 22 to pass a current through the arched beam 24 to give a current-carrying heat to the arched beam 24 to cause arching displacement of the arched beam 24, with the valve 30 moved in the direction of arching displacement via the actuator member 26. Conductive heating of the arched beam 24 and the stop of the conductive heating causes the arm 30a of the valve plate 30 to move between the closed position and the open position of a valve opening 40 provided in the substrate 50 to control the opening and closing of the valve opening 40.