A piezoelectric element (20) is attached to a vibration member (10). A plurality of electrodes (22) are two-dimensionally arranged on one surface of the piezoelectric element (20) so as to be spaced apart from each other. A supporting frame (40) supports an edge of the vibration member (10). A control unit (50) inputs an independent driving signal to each of the plurality of electrodes (22). Thus, a large output can be obtained with a resonance frequency depending on what signal is input to which electrode (22). For example, the piezoelectric element (20) is a resin film that is formed of a high molecular material indicating a piezoelectric property.
