To obtain a diaphragm device using a very compact electromechanical energy conversion element by providing an electromechanical energy conversion means for exciting a frequency by impressing a frequency voltage from the outside and driving a diaphragm actuating member.

Twelve electrodes 12 equally divided in the circumferential direction are stuck to one surface of an electromechanical energy conversion element 11 formed on a disk. An electrode 13 being a COM terminal is then stuck to the whole of the other surface. Furthermore, an elastic vibrating body 14 having plural pawls 14a is stuck to the electrode 12. Then, a rotor 15 rotating a driving arm 2 is energized by a spring, etc., to made it press-contact with the pawl 14a. By such constitution, the element 11 causes waveform vibration together with the vibrating body 14 by connecting a high frequency current power source between the six electrodes by every one out of the twelve electrodes 12 in the element 11 and the electrode 13 being the COM terminal and applying a high frequency.