To provide a capacitor device capable of preventing thermal interference between a filter capacitor and a plurality of smoothing capacitors. A capacitor device provided in an energization circuit between a power source and a semiconductor module as a power supply device includes a filter capacitor for removing a noise included in a current supplied from a power input terminal, a plurality of smoothing capacitors for smoothing a voltage, and a capacitor case that houses the filter capacitor and the plurality of smoothing capacitors, and a first gap between the filter capacitor and a smoothing capacitor provided at a position closest to the filter capacitor among the plurality of smoothing capacitors is configured to be larger than a second gap between two smoothing capacitors adjacent to each other among the plurality of smoothing capacitors.