PROBLEM TO BE SOLVED: To provide a system in a greenhouse having a simple structure which facilitates maintenance, while minimizing a space which needs thermal insulation.SOLUTION: In a system 1 for ascending/descending an inner roof in a greenhouse, a beam or horizontal material 2 built across between support pillars 3 of a greenhouse 10 supports a shaft 19 extending in a ridge direction in a rotatable state； and normal/reverse rotation of the shaft 19 vertically moves a suspension member 22 extending in a vertical direction, thereby ascending/descending an inner roof 40 for thermal insulation suspended by the suspension member 22. When a worker needs to take care of cultivated plants, the inner roof can be lifted higher than the worker's height, and when thermal insulation is needed, the inner roof can be descended to near the height of the cultivated plants.【課題】 簡素でメンテナンス容易な構成を備え、保温すべき空間を最小限に抑えることが可能な温室内システムを提供する。【解決手段】 温室１０の支柱３間に渡された梁または水平材２によって、棟方向に延びるシャフト１９を回転可能な状態で支持し、該シャフト１９の正逆回転によって鉛直方向に延びる吊り下げ部材２２を上下動させることで、該吊り下げ部材２２に吊り下げられた保温用の内屋根４０を昇降させ、栽培植物の手入れ作業をすべき時には作業者の身長より高く持ち上げ、保温すべき時には栽培植物の背丈近くまで降下させることが可能な温室の内屋根昇降システム１である。【選択図】図１
