A cable connection part structure includes a power control unit, a unit-side connector and a cable-side connector. The unit-side connector is connected to a power supply passage of an electric power control device and has a first connection terminal directed to a space below a unit case. The cable-side connector is connected to a power supply cable and has a second connection terminal connected to a first connection terminal from below the unit case. The cable-side connector has a connector case, and a bolt fixed to a connector case and having a shaft section passing upward through a part of the unit case from below. A nut is fastened to the shaft section of the bolt passing through the unit case from above.