An arc detection device includes a voltage detector connected between a first wire and a second wire to detect a voltage between the first wire and the second wire, the first wire connecting a positive electrode of a DC/DC converter and a plurality of DC/DC converters and branching from the positive electrode of the DC power source into the plurality of DC/DC converters, the second wire connecting a negative electrode of the DC/DC converter and the plurality of DC/DC converters and branching from the negative electrode of the DC/DC converter into the plurality of DC/DC converters; and an arc determiner that determines an occurrence of an arc based on the voltage detected by the voltage detector.