The present invention is a plant cultivation device. The water tank supplies cultivation water to the cultivation tank via an irrigation conduit. The water tank also suctions cultivation water from the cultivation tank via a water-sucking pipe. The heat-collecting part receives sunlight, and the pressure of air that is heated inside the air-storage part presses the surface of the water inside the water tank. The water tank supplies cultivation water that has been pressed by said air to a culture medium material. The heat-collecting part raises the surface of the water inside the water tank as a result of the heated air being cooled by a decrease in the sunlight. The water tank suctions cultivation water from a bottom section of the cultivation tank.
