An object of the present invention is to provide a polyglycerol medium-chain fatty acid ester-containing composition capable of forming a water-in-oil microemulsion, the microemulsion being capable of solubilizing a large amount of water, and the composition having excellent dispersibility and self-emulsifiability in water, and cosmetics comprising the composition. The present invention relates to a polyglycerol medium-chain fatty acid ester-containing composition comprising a polyglycerol medium-chain fatty acid ester formed by esterification of a medium-chain fatty acid having 6 to 10 carbon atoms and a polyglycerol having an average degree of polymerization of 3 or more and less than 100, and a nonionic surfactant and cosmetics comprising the polyglycerol medium-chain fatty acid ester-containing composition as defined above.