A resin composition that enables formation of a film superior in cold water solubility, mechanical strength, and chemical resistance is provided. The resin composition comprises a modified PVA comprising a monomer unit represented by formula (I), and an amine compound represented by formula (II): a content of the amine compound with respect to 100 parts by mass of the modified PVA being from 0.01 parts by mass to 1 part by mass. In the formula (I), R1 represents a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms; and R2 represents —R3—SO3−X+, —R3—N+(R4)3Cl−, or a hydrogen atom, R3 representing an alkanediyl group having 1 to 10 carbon atoms, X+ representing a hydrogen atom, a metal atom, or an ammonium group, and R4 representing a linear or branched alkyl group having 1 to 5 carbon atoms. In the formula (II), R5 represents —R3′—SO3−X+′, —R3′—N+(R4′)3Cl−, or a hydrogen atom.