PROBLEM TO BE SOLVED: To provide a method for improving a cognitive function in individuals suffering from a cognitive deficit and in healthy individuals (i.e., individuals that are apparently not suffering from a cognitive deficit).SOLUTION: A method for improving a cognitive function comprises administering to a subject (R)-7-chloro-N-(quinuclidin-3-yl)benzo[b]thiophene-2-carboxamide, or a pharmaceutically acceptable salt thereof, at a daily dose of less than 3 mg.SELECTED DRAWING: NoneCOPYRIGHT: (C)2020,JPO&INPIT【課題】認知障害に罹患した個体及び健康な個体(すなわち、見かけ上認知障害に罹患していない個体)において認知機能を改善する方法の提供。【解決手段】(R)-7-クロロ-N-(キヌクリジン-3-イル)ベンゾ[b]チオフェン-2-カルボキサミド又はその製薬上許容しうる塩を3mg未満の1日投与量で対象に投与することからなる、認知機能を改善する方法。【選択図】なし