POWER SUPPLY DEVICE, ON-BOARD POWER SUPPLY DEVICE, AND ELECTRIC AUTOMOBILE

A power supply apparatus includes: a power supply circuit; and a control section, the power supply circuit including a power factor improvement circuit that improves a power factor of alternating-current electrical energy by switching of a transistor; and a DC/DC conversion apparatus that converts by switching of a transistor at least one of a voltage and a current of the electrical energy whose power factor is improved by the power factor improvement circuit, the control section being configured to control switching timings of the power factor improvement circuit and the DC/DC conversion apparatus, wherein the number of the power supply circuit is N, and the control section controls the switching timings such that the switching timing of the power factor improvement circuit differs among the N power supply circuits, and that the switching timing of the DC/DC conversion apparatus differs among the N power supply circuits.