By contacting a bactericidal agent 2 with a liquid side surface 1b of a membrane 1, contacting a gas 3 with a gas side surface 1a of the membrane, and setting a pressure on the gas side lower than that of the liquid side, wherein a side of one surface 1b of the both surfaces of the membrane 1 is the liquid side and a side of the other surface 1a is the gas side, the inner part of the membrane is highly sterilized. In addition, a pressure difference generating mechanism constituted to perform this sterilization method is imparted to the gas-dissolved liquid manufacturing apparatus.
