An inverter device includes a substrate, upper arm elements, lower arm elements, positive and negative input electrodes, and an output electrode. The upper arm elements serve as an upper switching element and are arranged along a first direction. The lower arm elements serve as a lower arm switching element and are arranged along the first direction. At least one of bus bars of the positive and negative input electrodes and the output electrode extends parallel to the first direction. At least one of the bus bars of the positive and negative input electrodes and the output electrode has a length in the longitudinal direction that is greater than a width between two ends of the upper arm elements and the lower arm elements in the first direction.