PROBLEM TO BE SOLVED: To provide an overactive bladder preventing or improving agent that prevents and/or improves overactive bladder, or dysuria such as urinary urgency, urge incontinence.SOLUTION: An overactive bladder preventing or improving agent comprises, as an active ingredient, at least one selected from the group consisting of Brassica oleracea L. var. capitata extract, Yucca foam extract, Stevia rebaudiana extract, β-carotene, Monascus yellow pigment, Thymus vulgaris extract, Carthamus tinctorius extract, Nootkatone, mevastatin and Musa paradisiaca extract.SELECTED DRAWING: None