A piezoelectric transducer comprises a piezoelectric component, an acoustic member attached to one of the surfaces of the piezoelectric component and a dampening material of low elastic modulus attached to one or both surfaces of the piezoelectric transducer. In particular, it is possible to allow an increased number of PCB units to be simultaneously molded in a resin encapsulate molding process, thereby achieving a great improvement in the efficiency of the resin encapsulate molding process. The front ends of the transformer units are respectively connected to the driver units which are parallel connected to a power source.