A wire harness unit applied to a power storage device unit and a wire harness includes a routing material and a cooling unit that cools the routing material. The routing material constitutes a charging conduction path that extends between a charging inlet and a power storage device, and transmits electricity. The charging inlet is provided to a vehicle. The power storage device is provided to the vehicle and can store electric power. As a result, the wire harness unit, the power storage device unit, and the wire harness can reduce a cross-sectional area of the routing material to a relatively small area, thereby having an advantageous effect of capable of having proper mountability.