The present invention provides a hydroponic cultivation system capable of more reliably obtaining a forcing effect of a plant. A hydroponics system comprising cultivation tanks 1 and 2 for storing a nutrient solution 4 and growing a plant S, and a circulation pipe 7 for circulating and supplying the nutrient solution 4 to the cultivation tanks 1 and 2 is provided. And means 8 for generating floating bubbles B having buoyancy with respect to the nutrient solution 4 in the nutrient solution 4 and supplying them to the cultivation tanks 1 and 2 together with the nutrient solution 4, and the nutrients in the cultivation tanks 1 and 2 Means 3, 5, 9 for raising and lowering the water level WL of the liquid 4, and raising and lowering the water level WL of the nutrient solution 4, so that at least a part of the root N of the plant S is immersed in the nutrient solution 4； The state of being exposed from the nutrient solution 4 is repeated, and the time during which at least a part of the root N of the plant S is exposed from the nutrient solution 4 is set to be longer than the time of being immersed in the nutrient solution 4. [Selection] Figure 1【課題】植物の促成効果をより確実に得ることのできる水耕栽培システムを提供する。【解決手段】養液４を貯留して植物Ｓを生育する栽培槽１，２と、栽培槽１，２に養液４を循環供給するための循環配管７とを備えた水耕栽培システムであって、養液４に対して浮遊性を有する浮遊性気泡Ｂを養液４中に発生させて養液４とともに栽培槽１，２に供給する手段８と、栽培槽１，２内の養液４の水位ＷＬを上下させる手段３，５，９とをさらに備え、養液４の水位ＷＬを上下させることで、植物Ｓの根Ｎの少なくとも一部が養液４に浸される状態と養液４から露出する状態とが繰り返され、植物Ｓの根Ｎの少なくとも一部が養液４から露出する時間は、養液４に浸される時間よりも長いようにする。【選択図】図１
