The power supply system includes a first DC power source, a second DC power source, and a power converter having a plurality of switching elements and reactors. The power converter is configured to be switchable, by the control of the plurality of switching elements, between a parallel connection mode in which DC voltage conversion is executed with the DC power sources connected in parallel with a power line and a series connection mode in which DC voltage conversion is executed with the DC power sources connected in series with the power line. Each of the switching elements is arranged to be included both in a power conversion path between the first DC power source and the power line PL and a power conversion path between the second DC power source and the power line.