A lighting device for protecting plants from disease includes a light source for emitting light including ultraviolet rays. The light source radiates UV-B having wavelength components in a range of about 280-340 nm, UV-C having wavelength components in a range of about 100-280 nm from which wavelength components equal to or lower than about 255 nm have been removed, and visible rays having a peak among wavelength components having a wavelength distribution from 460 to 550 nm at least in an overlapping manner. A sum of irradiation of the UV-C and irradiance of the UV-B at a location where the UV-C and the UV-B come into contact with a plant is equal to or lower than about 50 µW/cm2, and irradiance of the visible rays at a location where the visible rays come into contact with the plant is equal to or higher than about 0.2 µW/cm2.
