Abstract: A drive assistance device for a hand-driven wheel chair has two running wheels, said running wheels being adapted to be detachably mounted to a wheel chair frame and being provided with hand rims for applying manual force. Each of said running wheels comprises a drive unit having an electric motor, a power supply and an electronic control unit associated thereto. Said complete drive unit including said electric motor, said power supply and said electronic control unit associated thereto is located in the region of the wheel hub. Preferably, said drive unit including said electric motor, said power supply and said electronic control unit associated thereto is adapted to rotate together with said running wheel.