To provide an in-vehicle power generation/storage facility capable of effectively generating power by utilizing the surplus energy generated during a travel of a vehicle and effectively storing it, effectively utilizing the electric energy thus stored, particularly the facility being provided with a power generation unit improved to efficiently increase the generation amount and effectively utilize the surplus energy.

The in-vehicle power generation/storage facility is employed which comprises a power generation unit and a power storage unit that are provided separately from a power unit used for the driving of a vehicle. The separately provided power generation unit is connected to an axle of the vehicle and is operated by the rotation power of the axle to generate electric energy that is stored in the separately provided storage unit. The in-vehicle power generation/storage facility utilizes the electric energy thus stored for other purposes than that of the vehicle. The separately provided power generation unit comprises a plurality of generators, a part of the plurality of generators or the whole generators being operated in accordance with a travel road surface and/or travel speed of the vehicle. The power storage unit comprises at least one storage battery.