To obtain a high-speed self-power supply type dimming element which shields harmful UV, converts the UV to electric power and does not require power supply from the outside and to obtain a self-power supply type dimming element which does not impair visibility and has the above functions.

At least a photovoltaic element with a semiconductor layer containing one or more of the group IIIA elements of the Periodic Table and one or more of the group VA elements and a dimming element which varies light transmittance by utilizing electric current or voltage generated by the photovoltaic element are laminated on a transparent electrically conductive substrate to obtain the objective self-power supply type dimming element. The group IIIA elements are preferably Al, Ga and In and the group VA elements are preferably nitrogen. The photovoltaic element is preferably transparent to visible light.