The present invention provides an aqueous liquid preparation having high stability to light and heat, which contains (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, and tyloxapol or octoxynol.