[Problem] To provide a photovoltaic device capable of generating power whether day or night, without affecting the appearance of a structure or reducing lighting or other functions, and able to inhibit rises in room temperature by converting thermal radiation into electrical energy.[Means to Solve Problems] Provide a photoelectric conversion element 3 with a photovoltaic device 1 on structural members 2a-2d facing the outside of a house or other structure. Power generated by the photoelectric conversion element 3 is extracted via a power extraction unit 4. The power conversion element 3 includes a semiconductor layer 11, conductive layer 20, a metal nanostructure 30 having multiple periodic structures 33, a first electrode 41 and a second electrode 42. The first and second electrodes 41, 42 are separated in the direction of the surface of the photoelectric conversion element 1 with the terminals 71, 81 of the power extraction unit 4 respectively connected.