A main object of the present invention is to provide a coating composition capable of maintaining an excellent moisture-proof property of coating compositions mainly comprising a polyvinyl alcohol polymer, as well as increasing the coating process speed and improving the productivity. The object is achieved by a coating composition comprising a polymer or copolymer (A) obtained by polymerizing or copolymerizing at least one polymerizable vinyl monomer in the presence of polyvinyl alcohol and/or a derivative thereof, and a cellulose-based polymer (B).