The present invention is a resin composition, including: a resin α1 having an aromatic dicarboxylic acid monomer unit A1 having a hydrophilic group, a dicarboxylic acid monomer unit B1 having no hydrophilic group, and an aromatic monomer unit C1; and a resin α2 having an aromatic dicarboxylic acid monomer unit A2 having a hydrophilic group, a dicarboxylic acid monomer unit B2 having no hydrophilic group, and an aliphatic monomer unit C2, wherein the resin α2 includes a monomer unit other than a monomer unit that constitutes the resin α1, and a mass ratio of a content of the resin α1 to a content of the resin α2 is 0.9 or more and 20 or less. According to the present invention, a resin composition that can be removed only with water while maintaining the heat resistance of polymer materials can be provided.