A DC/DC converter includes N converters connected in parallel and each having an inductor, a switching element, and a reverse-flow preventing element. Each converter is controlled at phases different from each other and such that a sum of switching frequencies F is out of a first non-selected frequency band. The inductor has an inductance that decreases as the switching frequency F increases. The switching element is controlled using the switching frequency F higher than a second non-selected frequency band of which upper and lower limit frequencies are 1/N of upper and lower limit frequencies of the first non-selected frequency band, and has a total gate charge such that a total loss is smaller than that in a case where the switching frequency F is set to be lower than the second non-selected frequency band.