NOVELTY - The light concentrator (100) has a first high refractive index layer (1), a first low refractive index layer (2), and a second high refractive index layer (3) stacked in sequence. The surface on first low refractive index layer side of first high refractive index layer has a periodic concavo-convex region (4).    USE - Light concentrator for stacked type light concentrator in solar cell (all claimed).    ADVANTAGE - The light receiving area of photoelectric conversion element is significantly reduced without reducing the conversion efficiently with respect to the light receiving area of light concentrator since thickness of light concentrator is small. Prevents reduction in the power generation amount due to temperature rise since light in wavelength band heating the photoelectric conversion element does not arrive at the photoelectric conversion element. Enhances power generation efficiency since light concentratable wavelength band is widened through which propagatable wavelength band spreads to the photoelectric conversion element by using the stacked type light concentrator and light concentrators and photoelectric conversion elements are adapted in the light concentrating wavelength band and band gap. The light concentrating type solar cell is easily manufactured since positional alignment is easy and solar cell and panel light concentrator are allowed to be separately manufactured. The low cost and high efficiency concentrating type solar cell in which the area of solar cell is reduced and conversion efficiency is enhanced is obtained due to combination of the solar cell and panel light concentrator. Provides high efficiency, low cost, and lightweight light concentrating type solar cell when light concentrating type solar cell is constituted using the panel light concentrator.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross sectional view of the light concentrator.    First high refractive index layer (1)    First low refractive index layer (2)    Second high refractive index layer (3)    Periodic concavo-convex region (4)    Light concentrator (100)