The present invention relates to a method for production of a coated preparation, characterized by coating a core material with a coating solution, the core material comprising an active ingredient, the coating solution comprising a) a resin composition obtained by copolymerization of polyvinyl alcohol having an average polymerization degree of 1300 or less, and at least one polymerizable vinyl monomer in a weight ratio of 6:4 to 9:1, b) water, and c) an organic solvent. The method for production make it feasible to efficiently coat a preparation such as a tablet, a granule, and a fine granule, etc. (a pharmaceutical drug, an animal drug, an agricultural chemicals, a fertilizer, or a food product) with the coating solution comprising a) the composition comprising the polyvinyl alcohol copolymer as the main component, b) water, and c) the organic solvent.