DC/DC CONVERTER

A DC/DC converter 1A includes a transformer 10, a primary-side switching circuit 11, a primary-side resonant circuit 12, a secondary-side rectifier circuit 13, and a control unit 14A that controls the primary-side switching circuit 11, in which the control unit 14A performs, when reducing an output of the secondary-side rectifier circuit 13 to a predetermined value or less from a first state in which all three phase differences among the respective legs of the first leg, the second leg, and the third leg of the primary-side switching circuit 11 are first phase differences, first phase shift control of simultaneously increasing two phase differences among the three phase differences and decreasing the remaining one phase difference or second phase shift control of simultaneously decreasing two phase differences among the three phase differences and increasing the remaining one phase difference.