To provide a plant cultivation device and method which do not require transfer work of a culture vessel in change of a nutritious liquid, and do not require separate installation of a nutritious liquid tank for a former half and a nutritious liquid tank for a latter half.SOLUTION: A plant cultivation device 1 comprises: a culture vessel 2 for storing a plant； a nutritious liquid tank 3 for storing a nutritious liquid； a supply path 41 for feeding the nutritious liquid to the culture vessel 2 from the nutritious liquid tank 3； a return passage 42 for collecting a surplus nutritious liquid discharged from the culture vessel 2 and then returning the surplus nutritious liquid to the nutritious liquid tank 3； and an ion exchange tower 6 having a bypass circuit 5 which is branched from at least any of the supply path 41 and the return passage 42 and then merges thereto, and in which an ion exchanger is filled in the bypass circuit 5.SELECTED DRAWING: Figure 1【課題】養液変更時に培養容器の移し変え作業が不要であり、かつ、前半の養液用タンクと後半の養液用タンクを別個に設置することが不要な、植物栽培装及び植物栽培方法の提供。【解決手段】植物を収容する培養容器２と、養液を貯留する養液タンク３と、養液を前記養液タンク３から前記培養容器２に送る供給路４１と、前記培養容器２から排出された余りの養液を回収して前記養液タンク３に返送する返送路４２と、前記供給路４１もしくは前記返送路４２の少なくとも何れかから分岐して再度合流するバイパス回路５を有し、前記バイパス回路５にイオン交換体を充填したイオン交換塔６を備える、植物栽培装置１。【選択図】図１
