To provide: an acid taste enhancing agent for enhancing the acid taste of a composition containing an acid ingredient using an ingredient of a natural sweetener； an acid ingredient-containing composition that has an enhanced acid taste； and a method for enhancing acid taste of a composition containing an acid ingredient.SOLUTION: Provided are: an acid taste enhancing agent in which rebaudioside A and mogroside V are incorporated in a mass ratio of 50:50 to 99:1； an acid ingredient-containing composition containing the acid taste enhancing agent； and a method for enhancing acid taste of an acid ingredient-containing composition in which a stevia extract containing rebaudioside A by 90 mass% or more and a mogroside V are incorporated into an acid ingredient-containing composition so that the blending ratio of rebaudioside A and mogroside V is rebaudioside A: mogroside V=50:50 to 99:1 (mass ratio).SELECTED DRAWING: None【課題】天然甘味料の成分を用いて、酸成分を含む組成物について酸味を増強するための酸味増強剤、酸味が増強されてなる酸成分含有組成物、及び酸成分を含む組成物について酸味を増強させる方法の提供。【解決手段】レバウディオサイドＡとモグロシドＶとを、質量比で５０：５０～９９：１の割合で配合する、酸味増強剤。該酸味増強剤を含有する、酸成分含有組成物。レバウディオサイドＡを９０質量％以上含有するステビア抽出物及びモグロシドＶを、レバウディオサイドＡとモグロシドＶの配合比が、レバウディオサイドＡ：モグロシドＶ＝５０：５０～９９：１（質量比）となるように、酸成分含有組成物に配合する、酸成分含有組成物の酸味増強方法。【選択図】なし
