A gate driving power source device can be miniaturized by sharing power source units, and a large current can be prevented from locally flowing in a single chip even when a short-circuit failure occurs in a multi-phase conversion circuit included in a power conversion device. There is provided a shared power source unit supplying a shared DC power source to a gate drive circuit provided in any one of a plurality of lower arms of multi-phase conversion circuits or any one of a plurality of upper arms of the multi-phase conversion circuit and gate drive circuits provided in upper arms or lower arms of other conversion circuits.