Provided is an esterification reaction product having high waterproof-film-forming properties, providing shiny feeling, and being excellent in moisture-retaining properties. The esterification reaction product is prepared by esterifying component A: 12-hydroxystearic acid polymer having a degree of polymerization of 7 or more, component B: fatty acid other than 12-hydroxystearic acid polymers, and component C: pentaerythritol.