PROBLEM TO BE SOLVED: To obtain a plant cultivation device and a plant cultivation method which are capable of further improving the quality and productivity of tubers.SOLUTION: A plant cultivation device 10 cultivates a plant body 30 which includes a nutrient body 31 having roots 32 and stolons 34 on which tubers 35 are formed, and comprises a partition member 22 which spatially partitions the roots 32 to which liquid 70 is supplied from the stolons 34 and the tubers 35. Then, the partition member 22 is designed to suppress movement of steam generated from the liquid 70 to a space B1 in which the stolons 34 and the tubers 35 exist.
