PURPOSE: To improve the safety with discharge of an corresponding electric charge of a battery voltage through a semi-conductor switch which is rectified and charged by a capacitor after boosted with a blocking oscillation type DC-AC inverter.

CONSTITUTION: When connection is made between contacted terminals 11 and 12 with a properly small resistance, electrostatic capacity between the two terminals increased because the terminal 12 is insulated. Since a voltage developing in a base coil 14 of a blocking oscillation transformer 13 oscillates corresponding to positive or negative of the high frequency, an electric charge charged by a capacitor 9 is discharged for a short space of time in contact with a human body. Therefore, the voltage between gate sources of FET 3 reduces and the resulting increase in the drain current causes the capacitor to be charged through a rectifying diode 5. The charge stored is discharged through a primary coil 18, thereby producing a spark between electrodes 20 and 21.