An object of the present invention is to provide a DC/DC power conversion apparatus that can reduce the average power consumption over a wide range of DC voltage ratios. A control circuit (120) changes a switching frequency f at which IGBTs S1 to S4 perform ON/OFF operation, in accordance with a voltage ratio k (k=V2/V1) for DC voltage conversion, based on the following expressions, such that a magnitude ΔI of a current ripple flowing in a reactor Lc is a predetermined constant value irrespective of the voltage ratio k. If 1≦k 2: f=(V1/(2×L×ΔI))×(k−2)/k