Hydroponic apparatusA culture tank (106) constituting a flow path through which the solution (50) flowsA nutrient solution (108) storing the solution (50) andA feed flow path 109 for introducing a solution liquid 50 from a 108 to a cultivation tankA discharge flow path (110) to guide the solution liquid (50) from the cultivation tank (106) to the solution (108)；A pump (107) for circulating the solution liquid (50) between the liquid feed tank (108) and the cultivation tank (106) through a supply flow (109) and a discharge flow path (110)；It is provided in the cultivation tankA discharge filter (202) for removing a predetermined foreign substance from a solution (50) flowing into a discharge passage (110) from a cultivation vessel (106) andEquipped withThe discharge filterReturnsThe liquid tank 50 has a function of suppressing the liquid level of the solution liquid 50 in the cultivation tank 106 from being raised to a position higher than a predetermined height position.水耕栽培装置(１００)は、養液(５０)が流れる流路を構成する栽培槽(１０６)と、養液(５０)を貯留する養液槽(１０８)と、養液槽(１０８から栽培槽(１０６)へ養液(５０)を導く供給流路(１０９)と、栽培槽(１０６)から養液槽(１０８)へ養液(５０)を導く排出流路(１１０)と、供給流路(１０９)および排出流路(１１０)を経由して養液槽(１０８)と栽培槽(１０６)との間で養液(５０)を循環させるポンプ(１０７)と、栽培槽(１０６)内に設けられ、栽培槽(１０６)から排出流路(１１０)へ流れ出る養液(５０)から所定の異物を除去する排出フィルタ(２０２)と、を備え、排出フィルタ(２０２)は、目詰まりした場合に、栽培槽(１０６)内の養液(５０)の液面が所定の高さ位置よりも上側に位置まで上昇することを抑制する機能を有する。
