Power supply apparatus and vehicle

A power supply apparatus that can be disposed below a floor panel of a vehicle, comprising:

• a wiring structural body that is disposed below the floor panel, and is routed such that a plurality of wire harnesses extend along the wiring structural body;
• at least one high-voltage electricity storage device that is disposed below the wiring structural body, and is connected to the plurality of wire harnesses;
• at least one low-voltage electricity storage device that is disposed below the wiring structural body, is connected to the plurality of wire harnesses, and outputs a voltage smaller than a voltage output by the high-voltage electricity storage device;
• and
• an electric device that is disposed below the wiring structural body, and is connected to at least one of the high-voltage electricity storage device and the low-voltage electricity storage device via the plurality of wire harnesses.