To provide a simple and inexpensive planting device functioning as a planting base for plant cultivation or greening planting when constructing rooftop greening or the like mainly of a building, and formed only by putting a thing obtained by superimposing water-permeable planting soil-enclosed cloth wrappers on a container of a rainwater-storing layer, on the floor board at an existing roof top.

The planting device is structured as follows: forming a drainage port 2 at the side surface of an elastic and water-impermeable container 1 at a height enough to keep a prescribed amount of water; and charging lightweight coarse fragments 3 up to the height of the drainage port to form a water-storage layer; and superimposing the weather-proofing water-permeable cloth wrapper 5 with which lightweight planting soil 4 mixed with artificial soil is wrapped and tied, on the water-storage layer.