A planting device includes an outer shell and an inner shell. The outer shell has a closed first cavity therein. The inner shell is disposed in the first cavity. The inner shell is formed with a second cavity having an opening. The second cavity is filled with soil. Plant seeds are placed in the soil. The opening of the second cavity is sealed with a first water-permeable layer. A side wall of the first cavity, opposite the opening of the second cavity, is a seepage layer. A retaining wall is provided around an outer side of the seepage layer to form a water storage trough. A method for manufacturing the planting device is provided. The planting device enables plants to grow out of the shell from a closed cavity, reducing the soil pollution to the environment and the impact on human health. It is convenient for planting, just watering.
