Disclosed is a container-packed sparkling beverage which has a moderated acidic flavor, which is smooth even after a person sweats, which a person can drink when hydration is desired and which is useful as a thirst-quenching beverage. The disclosed container-packed sparkling beverage contains the following components (A), (B) and (C): (A) grain-derived protein (B) potassium and (C) a frothing agent, wherein peptides having a molecular weight of 5000 or less (D) account for 70-100 mass% of component (A), the mass content ratio [(D)/(B)] of component (D) to component (B) is 15-300, and the pH is 3-5.
