To provide a method and an apparatus for producing carbonated water stably supplying carbonated water of high concentration of carbon dioxide gas providing physiological effect, regardless of flow rate of raw water.
Continuously supplied raw water and carbon dioxide gas are supplied to a carbon dioxide gas dissolver 5 to produce carbonated water dissolved with carbon dioxide gas. The variation of the gas solubility in carbonated water production is measured by detecting the gas variation amount in a gas separation vessel 14, by a raw water flow detecting means 3 and a carbon dioxide gas flow detecting means 10. The data are sent to a control device 15 having an operation part, and the gas variation amount in a unit time is operated by the operation part of the control device from the difference between the detected data and a reference gas amount stored in the control device in advance. Based on the gas variation amount in a unit time, a flow rate control means of the raw water and/or the flow rate control means of carbon dioxide gas is controlled by the signals outputted from the control device 15 to the flow rate control means of the raw water and/or the flow rate control means of carbon dioxide gas.