Provided is a skin moisture-retention improving agent that contains, as an active ingredient, a specific cyclic dipeptide having amino acids as structural units, or a salt thereof. Also provided are a use of said agent to improve moisture-retention in skin, a method for improving the moisture-retention of skin, and the like. The specific cyclic dipeptide was found to have an action of remarkably improving the moisture-retention of skin. The agent according to the present invention provides a novel agent for improving the moisture-retention of skin that contains, as an active ingredient, a cyclic dipeptide having high fat-solubility and excellent gastrointestinal permeability and membrane permeability.
