To provide a production method of gas dissolved water, capable of efficiently producing gas dissolved water with a high concentration without using a large amount of a gas; and a production unit and a production apparatus used for producing the gas dissolved water.

As shown in Fig. 1, in a membrane module 10B, dry air is supplied into a gas phase chamber 12B and a liquid phase chamber 11B. With this dry air, the gas phase chamber 12B, the liquid phase chamber 11B, and a gas-permeable membrane 13B are dried. The dry air supplied into the gas phase chamber 12B passes through a gas extraction piping 51B and, after the measurement of humidity with a hygrometer 52A, is discharged. The dry air supplied into the liquid phase chamber 11B is discharged through a piping 22B. In a membrane module 10A, raw water is supplied through a raw water piping 20A into a liquid phase chamber 11A of the membrane module 10A, and a gas is supplied through a gas supply piping 40A into a gas phase chamber 12A of the membrane module 10A.