PURPOSE: To improve the utility by regenerating the energy, which is stored in an absorber capacitor, in the power source of a gate circuit and applying this method to a self-extinction of are type thyristor (SCTH) performing a high-frequency operation.

CONSTITUTION: For the purpose of are extinguishing an SCTH 1, a switching element 6 is closed to supply a reverse gate current from a DC power source 4 to the SCTH 1. When the SCTH 1 is are extinguished, a main circuit current charges a capacitor 2 through a diode 3, and the rapid rise of the voltage between an anode A and a cathode K of the SCTH 1 is prevented to perform an absorber action. For the purpose of igniting the SCTH 1, the switching element 6 is opened and a switching element 6' is closed. Then, a positive gate current is supplied from a DC power source 4', and the SCTH 1 is ignited. When the SCTH 1 is made conductive, electric charge stored in the capacitor 2 is discharged to charge a capacitor 8, and the energy is supplied to a reactor 5. The energy of a reactor 5 is transferred to the capacitor 8 finally, and the energy stored in the capacitor 8 is regenerated in the DC power source through the reactor 9.