The present invention provides a stable and clear aqueous liquid preparation containing (3-{2-[4-isopropyl-2-(4-trifluoromethyl)phenyl-5-thiazolyl]ethyl}-5-methyl-1,2-benzisoxazol-6-yl)oxyacetic acid or a pharmaceutically acceptable salt thereof as an active ingredient, and benzalkonium chloride represented by the formula:[C6H5CH2N(CH3)2R]Clwherein R is an alkyl group having 8-18 carbon atoms.