PROBLEM TO BE SOLVED: To provide a hydroponic apparatus in which consumption of nutrition due to respiration by lower leaves may be reduced.SOLUTION: A hydroponic apparatus 100 comprises: a cultivation tank 1 which is constructed to store an aggregated nutrition accumulation part of a plant 10； and a ground surface part 3 attached to the cultivation tank 1 in a manner where overground space 130 at which overground part of the plant 10 grows is separated from underground space 120 at which underground part of the plant 10 grows. The cultivation tank 1 comprises a peripheral wall part 1b which may be stretched in vertical direction so that the height of the underground space 120 may be increased/decreased. The ground surface part 3 comprises an opening part 3a which is constructed so that a stem 16 extending from the aggregated nutrition accumulation part is inserted thereinto. The opening part 3a is constructed so that, when the peripheral wall part 1b is extended under a state where the stem 16 has been inserted into the opening part 3a, lower leaves 12 of the plant 10 may pass through the opening part 3a.SELECTED DRAWING: Figure 1【課題】下位葉の呼吸に起因した栄養分の消費を低減することができる水耕栽培装置を提供する。【解決手段】水耕栽培装置１００は、植物１０の塊状栄養蓄積部が収容されるように構成されている栽培槽１と、植物１０の地上部が成長する地上空間１３０と植物１０の地下部が成長する地下空間１２０とを仕切るように栽培槽１に取り付けられた地表面部３とを備え、栽培槽１は、地下空間１２０の高さを増減するように上下方向において伸縮する周壁部１ｂを含み、地表面部３は、塊状栄養蓄積部から延びる茎１６が挿入されるように構成された開口部３ａを含み、開口部３ａは、茎１６が開口部３ａに挿入された状態で周壁部１ｂを伸長させたときに、植物１０の下位葉１２が開口部３ａを通過できるように構成されている。【選択図】図１
