A piezoelectric transformer 101 includes a piezoelectric element 506. Two primary side electrodes 507A, 507B exist on the primary side of the piezoelectric element 506. The primary side electrodes 507A, 507B are coupled by a resistor 515 formed from a conductive coating. A discharge current is discharged via the resistor 515 to protect a semiconductor component from the discharge current. Since neither a short-circuit terminal nor conductive jig is required, electrostatic discharge damage to a semiconductor component can be prevented by a low-cost arrangement.