A DC/DC converter has three half-bridge-type current resonant DC/DC converters that are connected in parallel, have a phase difference of 120 degrees, and are operated at a frequency higher than a resonant frequency. Each of the three half-bridge-type current resonant DC/DC converters includes a transformer having a primary winding, a secondary winding, and a tertiary winding, a series circuit connected to both ends of a DC power source and including first and second switching elements, a series circuit connected to both ends of the first or second switching element and including a resonant reactor, the primary winding of the transformer, and a resonant capacitor, and a rectifying circuit to rectify a voltage generated by the secondary winding and output the rectified voltage to a smoothing capacitor. The tertiary windings are annularly connected to a reactor.