A method of producing a milk-containing beverage is provided which can effectively suppress foaming in the raw milk occurring in the production process while greatly reducing the dissolved oxygen concentration of the milk-containing beverage. This milk-containing beverage production method involves: (A) a first oxygen concentration reduction step in which the supply method and supply conditions in an inert gas treatment are controlled, the raw milk is subjected to the inert gas treatment such that the foam ratio of the raw milk is less than or equal to 10%, and thereafter, the raw milk is discharged to obtain raw milk with a reduced dissolved oxygen concentration； (B) a second oxygen concentration reduction step in which the supply method and supply conditions in an inert gas treatment are controlled, the raw milk obtained in step (A) is subjected to inert gas treatment such that the foam ratio of the raw milk is less than or equal to 10% to obtain raw milk with reduced dissolved oxygen concentration； and (C) a heating sterilization step for heat-sterilizing the raw milk obtained in the step (B).
