The present invention provides an illumination apparatus for plant cultivation, including a unit configured to change light in any wavelength region of 300 nm or higher and 600 nm or lower (wavelengths of 452 nm to 474 nm, for example) to light in the wavelength region having dominantly a right-circularly polarized light component. The illumination apparatus of the present invention enables irradiation with light that is capable of giving a specific effect in plant cultivation.
