The purpose of the present invention is to provide: a technique for promoting hyaluronic acid synthesis by a hyaluronic acid-producing cell； a method for evaluating the responsiveness of a hyaluronic acid-producing cell to a compound； or a method for evaluating the responsiveness of a polysaccharide derivative represented by formula 1 in the description or a salt thereof to a hyaluronic acid-producing cell. By bringing a polysaccharide derivative represented by formula 1 in the description or a salt thereof into contact with a hyaluronic acid-producing cell, the synthesis of hyaluronic acid is successfully promoted in the hyaluronic acid-producing cell. By using the polysaccharide derivative or a salt thereof for a hyaluronic acid-producing cell, the responsiveness of the hyaluronic acid-producing cell can be evaluated using hyaluronic acid production as an index. By using a hyaluronic acid-producing cell, furthermore, the responsiveness of the polysaccharide derivative or a salt thereof can be evaluated using hyaluronic acid production as an index.
