PROBLEM TO BE SOLVED: To efficiently irradiate plants with light for promoting growth while lightening psychological burden to an operator.SOLUTION: Synthetic light of emitting light from an illumination part for growth and emitting light from an auxiliary illumination part has a first peak of photon flux in a wavelength of 400 nm or more and 500 nm or less, and has a second peak of photon flux in a wavelength of 600 nm or more and 700 nm or less. Photon flux of each wavelength in 500 nm or more and 600 nm or less in the synthetic light is smaller than the photon flux of the first peak and the second peak.COPYRIGHT: (C)2015,JPO&INPIT【課題】作業者の心理的負担を軽減しつつ、植物に対し、成長促進のための光を効率的に照射する。【解決手段】成長用照明部の出射光と補助照明部の出射光との合成光は、400nm以上500nm以下の波長に光量子束の第1ピークを有し、600nm以上700nm以下の波長に光量子束の第2ピークを有し、合成光における500nm以上600nm以下の各波長の光量子束は、第1ピーク及び第2ピークの光量子束よりも小さい。【選択図】図5
