A high conversion efficiency inverter circuit by providing the current-mode resonant type efficient in using a power source.A current-mode resonant inverter circuit comprises a step-up transformer; the secondary winding side of the step-up transformer is composed of a resonant circuit between leakage inductance of the step-up transformer secondary winding and a capacitive component present in the secondary side circuit; one end of the step-up transformer primary winding is connected to the power source side; the other end of the primary winding is connected to a switched snubber circuit through the primary winding of a current transformer; the switched-snubber circuit comprises a pair of transistors different from each other in polarity; bases or gate of the pair of transistors, connected to each other, are connected to the secondary winding of the current transformer; either collector of the pair of transistors is connected to the primary winding of the current transformer; the other collector of the transistor is connected to the current transformer primary winding through a capacitor.