The purpose of the present invention is to provide an acidic liquid beverage in which dispersion of a protein in a liquid is stably maintained and settling does not readily occur over a long period of time even when a relatively large amount of the protein is blended in the liquid beverage. An acidic protein beverage characterized in that at least one raw material containing a protein is a powdered protein material satisfying a specific condition, the protein content is 1 wt% or greater, a soybean polysaccharide and/or a pea polysaccharide is included as a protein dispersion stabilizer, and the acidic protein beverage is liquid and has a pH of 3-5.
