PROBLEM TO BE SOLVED: To provide a plant cultivation instrument which is inexpensive, capable of maintaining satisfactory cultivation environment even if it is used for a long period of time, and promoting growth of plants.SOLUTION: A plant cultivation instrument 1 for hydroponics comprises: a nutritious liquid tank 10 in which nutritious liquid 2 is housed a cultivation tank 20 as a partition member which partitions the nutritious liquid tank 10 into an upper part and a lower part and a holding plate 30 as a plant holding member disposed above the nutritious liquid tank 10, in which the cultivation tank 20 includes: an air permeating part 23 for moving air bubbles generated by supplying air to the lower part of the nutritious liquid tank 10 to the upper part of the nutritious liquid tank 10 and a liquid permeating part 24 for moving the nutritious liquid 2 in the upper part of the nutritious liquid tank 10 to the lower part of the nutritious liquid tank 10, the air permeating part 23 is constituted by including: an air bubbles collecting part 23a having a shape capable of collecting air bubbles and an air permeating hole 23b for allowing air bubbles collected in the air bubbles collecting part 23a to pass through.