A power conversion device includes a semiconductor stack, a reactor, and a capacitor. The semiconductor stack includes a plurality of semiconductor modules stacked on one another in a stacking direction. Each semiconductor module includes a semiconductor element. The reactor constitutes a boost circuit that boosts a direct-current voltage. The capacitor is electrically connected to the plurality of semiconductor modules. The semiconductor stack, the reactor, and the capacitor each include a coolant flow passage, and the reactor and the capacitor are located adjacent to each other.