PROBLEM TO BE SOLVED: To provide a luminaire which can emit light to provide a specific effect in a plant cultivation.SOLUTION: A luminaire for plant cultivation comprises: means which converts light having wavelength region between 300 nm and 600 nm inclusive (for example, 452-474 nm) into light having wavelength region which preponderantly includes a right-handed circularly polarized light component； and means which converts light having wavelength region between 452 nm and 474 nm into light having wavelength region between 452 nm and 474 nm which preponderantly includes a right-handed circularly polarized light component. The luminaire for plant cultivation substantially emits unpolarized light in at least one part of wavelength region between 601 nm and 800 nm, or does not substantially emit light in at least one part of wavelength region between 601 nm and 800 nm.【課題】植物の栽培において特定の効果を与えることが可能である光の照射が可能な照明装置を提供する。【解決手段】植物栽培用の照明装置として、３００nm以上６００nm以下のいずれかの波長域（例えば、波長４５２nm～４７４nm）の光を、右円偏光成分を優勢に含む波長域の光に変更する手段を含んだり、また、波長４５２nm～４７４nmの光を、右円偏光成分を優勢に含む波長４５２nm～４７４nmの光に変更する手段を含んだり、また波長６０１nm～８００nmの少なくとも一部の波長において実質的に非偏光を出射するか、または波長６０１nm～８００nmの少なくとも一部の波長において実質的に光を出射しない照明装置である。【選択図】図１
