PURPOSE: To obtain a thin-gage sound generator and sound receiver having a wide range and high sensitivity, by setting two sheets of diaphragm opposite to each other and then giving the connection and vibration to both diaphragms via an air layer.

CONSTITUTION: A sheet of diaphragm 11 is set via an air layer 10 and opposite to a metallic diaphragm 1 to which a piezoelectric ceramics 2 is adhered. The diaphragm 1 vibrates with the AC signal applied through an air terminal 4 which is connected to the diaphragm 1 and the ceramics 2. the vibration of the diaphragm 1 is transmitted to the diaphragm 11 via the layer 10. As a result, the frequency- sensitivity characteristics has two peaks to relaize a thin-gage sound generator and sound receiver having a wide range and high sensitivity.