An output voltage is suppressed from changing and high efficiency is realized in a power conversion apparatus capable of performing a step-up/step-down operation. In a power conversion apparatus including a DAB DC/DC converter, when energy transmitted from a primary side and energy accumulated in a reactor at a secondary side are output from the secondary side, of a control signal of a first switching element and a control signal of a fourth switching element which are both in ON states, the first and fourth switching elements being diagonal to each other in a full bridge at the primary side, a period Toff2 in which the control signal of the first switching element is turned off before the control signal of the fourth switching element is turned off is controlled, and thereby a step-up/step-down ratio is continuously changed.