PROBLEM TO BE SOLVED: To provide an ambience conditioning system for a plant capable of properly keeping both temperature and humidity for the plant while keeping illuminance for the plant. SOLUTION: This ambience conditioning system for a plant has such a construction that benches 15 each housed with raising seedling chambers 14 each with the front face opened housed with raising seedling trays 21 are installed in an air-conditioned chamber 10 fed with conditioned air, a draft chamber 22 functioning to suck the conditioned air in the chamber 10 via the raising seedling chambers 14 is installed on the back of each of the benches 15, an illuminator 27 is set up on the ceiling 26 of each of the raising seedling chambers 14 and a screen filter 28 is furnished right under the illuminator 27 to partition an illuminating chamber 30, the back of which is made to communicate with the draft chamber 22.
