PURPOSE: To reduce switching loss, and to reduce the size of a device by using a high speed IGBT for first and third switching elements, and by using an IGBT of low ON-voltage for second and fourth switching elements.

CONSTITUTION: A high frequency resonance current is let flow in a load circuit 14 consisting of a heating coil 12 and a resonance capacitor 13, to form a high frequency magnetic field by the coil 12, and power is thus supplied to a pan on the coil 12. The power is freely changed by changing the ON-time of a second switching element 15a, and of a fourth switching element 17b. An IGBT of low ON-voltage Vce (Sat) is used to drive these elements. At the time of turning off where turn-off loss is generated, first and third switching elements 15a, 17a of fast switching speed are operated. Loss of switching element is reduced, and a small induction heating cooker is thus provided at low cost.