Provided is a containerized beverage containing a high concentration of isoquercitin and sugar adducts thereof, reducing the acidic aftertaste and the bitter, astringent aftertaste. This containerized beverage contains the following components (A) and (B): (A) 0.03-0.17 mass% of isoquercitin and sugar adducts thereof, and (B) 0.0001-2 mass% of an amino acid and has pH of 2-5.
