In a plant cultivation device (50), cultivation water (Cw) is circulated between a cultivation tank (20) and a pump (40) that operates by solar heat. The sink (20) surrounds a lower part of a support vessel (27). The pump (40) includes a water tank (30), a heat collecting unit (45), and a watering channel (36) and a recovery channel (33) including check valves (42 and 41), respectively. The water tank (30) and the heat-collecting unit (45) form one continuous airtight air containing part. The heat-collecting unit (45) includes an air tank (44). A watering channel (36) supplies the cultivation water (Cw) from the water tank (30) to a culture medium material (Ps) from above the culture medium material (Ps). The recovery channel (33) is connected to the sink (20). Bubbles (Bb) are supplied from a nozzle (16) to the lower part of the support vessel (27). Air that has formed the bubbles (Bb) is supplied to the culture medium (Ps) from a lower part thereof.
