Disclosed are: a benzylamine derivative typified by the formula below and a pharmaceutically acceptableacid addition salt thereof； a pharmaceutical agent comprising the derivativeor the pharmaceutically acceptable acid addition salt thereof； and a therapeuticor prophylactic agent for frequent urination or urinary incontinence, whichcomprises the derivative or the pharmaceutically acceptable acid addition saltthereof. The benzylamine derivative and the pharmaceutically acceptable acidaddition salt thereof have reduced adverse side effects compared to conventional compoundsand high therapeutic effect on frequent urination or urinary incontinence. Therefore,the benzylamine derivative and the pharmaceutically acceptable acid additionsalt thereof can be used as an excellent therapeutic or prophylactic agent forfrequent urination or urinary incontinence.
