A step-down chopper circuit having a filter reactor includes: a capacitor series circuit having a first capacitor and a second capacitor; a first series circuit having a semiconductor switching element and a diode, which is connected in parallel with the first capacitor, and a second series circuit having a diode and a semiconductor switching element, which is connected in parallel with the second capacitor; a chopper reactor whose one end is connected to a connection point of the first series circuit; and an output capacitor connected between the other end of the chopper reactor and a connection point of the second series circuit, in which a bypass current path with respect to the capacitor, which is configured to bypass a short-circuit current, is formed when one of the first series circuit and the second series circuit becomes a short-circuit state.