The capacitor module includes a capacitor, in which a screw hole is arranged on an outer bottom wall surface of a capacitor case housing a capacitor element, and a heat dissipater, on which a plurality of capacitor cases are fixated by screwing fixation screws in the screw holes of the capacitors. As a result, for example, the capacitor can be fixated with reliability and durability secured even under a condition where very strong vibration is continuously applied, for example, when the capacitor module is mounted on construction machinery. Further, because, an adherence of the outer bottom wall surface of the capacitor case on a fixation surface of the heat dissipater is strengthened by screwing the fixation screw in the screw hole, the capacitor can be cooled down by transferring heat produced by the capacitor to the heat dissipater as needed.