To provide a hydroponic method comprising sterilizing hydroponic nutrient solution with ozone water, making the solution contain a large quantity of oxygen, and supplying the nutrient solution to a water passage for supplying the nutrient solution so as to promote growth of plants; and to provide a hydroponic device including a device for supplying the nutrient solution.

The hydroponic method comprises: producing ozone water the ozone concentration of which is maintained at ≥20 PPM for one hour or more while the ozone water is left in atmospheric pressure at 20°C as it is by making the water contain a large quantity of ozone air bubbles each having a diameter of ≤30 μm; admixing the ozone water to the hydroponic nutrient solution to perform sterilization; and supplying the ozone water-mixed sterilized nutrient solution where the ozone concentration is ≤3 PPM and the concentration of remaining oxygen is ≥10 PPM, to the roots of an objective plant 26 through a water passage 28 where the objective plant 26 is placed. The method enables more efficient supply of highly concentrated oxygen to the objective plant than a method comprising bubbling or the like.