A system corresponding to a plurality of different power sources (overhead contact line, power generator driven by engine, and fuel cells) is proposed as a method of using an optimum power supply in an electrified route and a non-electrified route. However, since different power converters are necessary for each power source, there are problems of an increase in the weight of a multi-car train, a reduction in the degree of freedom in composing a multi-car train because a mounting space needs to be reserved, an increase in the maintenance cost, a reduction in the reliability caused by an increase in the number of components, and the like. Provided are: a power conversion circuit that includes AC input ends, the number of which corresponds to the maximum number of phases among a plurality of different AC power supplies, and that converts AC power to a direct current; and switching means for switching a connection state of the AC power supplies and the power conversion circuit, wherein the connection state is switched according to the power supplies.