Gas dissolving device

The invention relates to a gas dissolving device having high processing power and capable of efficiently dissolving gas in water. A gas dissolving device (1) comprises a vessel body (2) having a sealed space, a gas supplying mechanism (3) provided with a supply tube (3b) connected to the vessel body (2), so as to supply a gas to the vessel body (2) through the supply tube (3b) until the gas pressure in the vessel body (2) is increased to the atmospheric pressure or above, a water supply mechanism (4) provided with water supply tubes (4a, 4b) connected to the vessel body (2), so as to supply water to the vessel body (2) through the water supply tubes (4a, 4b), and a drain tube (5) for discharging the gas-dissolved water stored in the bottom of the vessel body (2) to the outside, the arrangement being such that gas is dissolved in water by bringing gas and water into gas-liquid contact in the vessel body (2). The water supply tube (4a) is vertically disposed in the vessel body (2) and is provided with a delivery port (4c) which opens to the upper end surface, the arrangement being such that water is delivered from the delivery port (4c) upwardly toward the ceiling of the vessel body (2). The water supply tube (3b) is connected to the water supply tube (4a) to supply a gas to the vessel body (2) through the water supply tube (4a).