To provide a plant cultivation unit readily forming a culture medium in which a plant is grown without using culture soil and readily carrying out maintenance even in the case of a long-period cultivation.

In the plant cultivation, a culture layer 12 for plant cultivation is so formed that water fed into a cultivation container 11 is absorbed so as to enable water retention, by housing slips of paper 16 decomposed into small pieces in a cultivation container 11. A plant 13 having roots is arranged so that a part of root 13a is positioned in at least one of the upper part and the inner part of the culture layer 12. The culture layer 12 is used as a culture medium for the plant 13.