The invention provides a lighting device for a plant cultivation, which includes a unit for changing light of any wavelength region (i.e., a wavelength from 452 nm to 474 nm) ranging from 300 nm to 600 nm to the light of the wavelength region adequately including a right circularly polarized light component. According the lighting device of the invention, light could be emitted to provide a specific effect especially in the plant cultivation.本發明提供一種照明裝置，其是植物栽培用的照明裝置，其包括將300 nm以上、600 nm以下的任一波長區域(例如波長452 nm~474 nm)的光變更成充分包含右圓偏光成分的上述波長區域的光的單元。藉由本發明的照明裝置，而可照射尤其能夠在植物的栽培中賦予特定的效果的光。
