PROBLEM TO BE SOLVED: To provide the subject unit capable of realizing water holding and maintaining of a plant rearing material for a long period even in the case of no water absorption and maintaining the life of a cultivated plant for a long period by providing a water absorbing part having a specific water absorbing power. SOLUTION: This plant cultivation unit 10 is obtained by placing a container body 20 having the opened top and provided with water absorbing parts 24 in the outer part of the bottom 22 on a water storage tank and is capable of forming a water storage space 40 between the bottom 22 of the container body 20 and the bottom 32 of the water storage tank. The plant cultivation unit 10 is composed so that water in the water storage space 40 is absorbed by the water storage space 40 in many stages and the water absorbing power thereof is weakened toward a height close to the bottom 32 of the water storage tank. At this time, the positions at the lower end of the water absorbing parts 24 are preferably set at a prescribed height without reaching the vicinity of the bottom 32 of the water storage tank. The plural water absorbing parts 24 are preferably installed at stepwise heights.
