NOVELTY - The device (15) has a plate-shaped mount frame (17) positioned on a roof (13) of an electric vehicle (10) at horizontal direction while providing an electric power generation board (18a) for receiving sunlight in an upper surface i.e. light-receiving surface, of the mount frame. Another electric power generation board (18b) is supported below the former board such that movement in horizontal direction is possible on the mount frame. A fixing unit (20) is engaged/disengaged between the latter board and the mount frame. An operating handle (20a) is protruded from the mount frame.    USE - Auxiliary charging device for charging a storage battery for an electrical vehicle i.e. passenger car, using a solar panel.    ADVANTAGE - The board receives sunlight in the upper surface of the mount frame such that a movement of the board is possible even if the electric vehicle moves, so that the sunlight is received and an electric power is generated at a stopped place without requiring attachment or detachment of the boards. The other board and a third board are supported from the former board such that the movement in the horizontal direction is possible, so that the latter board and the third board can be expanded to a side of the former board, thus receiving light in an area wider than the roof in the former board. The latter and the third boards are installed below the former board such that the movement of the horizontal direction by the fixing part is latched, so that the need for unnecessary expansion of light-receiving area of the boards during driving of the electric vehicle can be eliminated without generating noise, thus enabling driving of the vehicle in a safe and stable manner.    DETAILED DESCRIPTION - The electric power generation board is a solar panel like electric power generation board.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of an electric vehicle.    Electric vehicle (10)    Roof (13)    Auxiliary charging device (15)    Plate-shaped mount frame (17)    Electric power generation boards (18a, 18b)    Fixing unit (20)    Operating handle (20a)