An electric power converter circuit includes a rectifying circuit having diodes, a coil, and a full-bridge circuit including switching devices, which are connected in cascade to an AC power supply 1, to convert an AC to a DC and to further convert the concerted DC to an AC. The converter circuit further includes a series circuit having a capacitor and a switching device, and connected between the DC terminals of the full-bridge circuit. One of the switching devices on the upper arm and one of the switching devices on the lower arm are turned simultaneously ON for a certain period of time. The electric power converter circuit facilitates reducing the number of the constituent parts, size, weight and manufacturing costs thereof.