Low molecular weight acetylhyaluronate has the following characteristics: intrinsic viscosity: 50 to 200 cm.sup.3 /g substitution degree of acetyl group: 2.6 to 3.6 (excluding N-acetyl group) A skin-softening composition is mainly composed of this low molecular weight acetylhyaluronate. It can exhibit excellent skin-softening effect and moisturizing effect, while appropriately suppressing the thread-forming ability inherent in hyaluronic acid. A method of manufacturing acetylhyaluronate comprises the steps of suspending hyaluronic acid powder in an acetic anhydride solvent and then adding concentrated sulfuric acid thereto to effect acetylation. A method of purifying acetylhyaluronate comprises the steps of adding raw acetylhyaluronate to an aqueous acetone solution, adding and dissolving sodium lactate therein, and then adding highly concentrated acetone thereto to precipitate highly pure acetylhyaluronate. Acetylhyaluronate having highly purity can be obtained inexpensively.