A luminescent substance particle including BaSnO3 having a perovskite-type structure, wherein the luminescent substance particle contains one of 0.07% by mass or less of Fe (iron), 0.005% by mass or less of Cr (chromium) and 0.02% by mass or less of Ni (nickel). A wavelength conversion film including the luminescent substance particle for converting a light in an ultraviolet region to a light in an infrared region. A wavelength conversion device including a substrate and the wavelength conversion film formed on the substrate.