PROBLEM TO BE SOLVED: To obtain a hyaluronic acid production-reinforcing agent which is a specific cyclic phosphoric acid ester capable of activating cells and enhancing the production and secretion of the hyaluronic acid for preventing the atrophy of a skin caused by the calendar aging of the skin or the repeated administrations of a steroid and the formation of a scar after the sure of a wound, and a composition combinedly using this agent, a promoting agent for expression of a gene of a hyaluronic acid producing enzyme, a cell activating agent, and specific cyclic phospholipids. SOLUTION: The hyaluronic acid production-reinforcing agent for animal cells contains a phosphate derivative expressed by formula (I) (wherein, RO is an 8-22C alcohol residue or a fatty acid residue and M is H, an alkali metal atom, an alkaline earth metal atom, a substituted ammonium group or non- substituted ammonium group) as an active ingredient.
