A series resonant converter circuit that reduces power loss is provided that includes an inverter circuit having at least a pair of first and second switching elements that is connected between DC input terminals, a transformer connected to this inverter circuit, a resonant inductance means that are connected in series to a primary winding wire or a secondary winding wire of the transformer, a primary-side resonant capacitor that is connected in series to the resonant inductance means through the first or second switching element, first and second secondary-side resonant capacitors that are connected to each other in series between the DC input terminals, first and second unidirectional elements that are connected to each other in series between the DC output terminals, and a resonant inductance means that cooperates with resonant capacitance from the primary-side resonant capacitor and the first and second secondary-side resonant capacitors to resonate in series.