PROBLEM TO BE SOLVED: To provide a low-cost, environmentally friendly, and easily handled hydroponics system which is capable of stably producing high-safety vegetables even if a circulating nutritious liquid is not discarded but reused.SOLUTION: A hydroponics system 10 comprises: a cultivation tank 2 for allowing a nutritious liquid to flow through the tank and to cultivate plants a purification treatment part 1 which purifies a nutritious liquid to be treated which is discharged from the cultivation tank 2 a supply line for nutritious liquid to be treated which supplies the nutritious liquid to be treated to the purification treatment part 1 and a supply line for treated nutrient liquid which supplies a treated nutritious liquid purified in the purification treatment part 1 to the cultivation tank 2, in which the purification treatment part 1 is equipped with a UVLED11 which irradiates the nutritious liquid to be treated with ultraviolet light.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】 循環養液を廃棄することなく再利用しても安全性の高い野菜の安定生産が可能であり、低コストで環境にやさしく、取り扱いの容易な水耕栽培システムを提供する。【解決手段】 水耕栽培システム10は、養液を通水させて植物を栽培するための栽培槽2と、栽培槽2から排出された被処理養液を清浄化処理する清浄化処理部1と、被処理養液を清浄化処理部1へと供給する被処理養液供給ラインと、清浄化処理部1で清浄化処理された処理済み養液を栽培槽2へと供給する処理済み養液供給ラインとを備え、清浄化処理部1が、紫外線を被処理養液に照射するUVLED11を備える。【選択図】 図1