Electronic components included in a power conversion unit are housed in a closed section of a first unit, and the first unit includes a heat sink exposed to an open section and releases heat transferred from the electronic components. A blower is housed in a first space of a second unit, and at least a portion of an impeller of the blower is exposed to a second space from an opening. A reactor is housed in a third unit. Outside air flows through a flow inlet into an interior of the power conversion device, passes through the open section, a first vent, the second space, the opening, the first space, a second vent, and the third unit, and then is discharged to the exterior of the power conversion device from a flow outlet.