To provide a method for producing an oxazoline group-containing polymer, in which the oxazoline group-containing polymer excellent in cross-linking property can be produced, in which an oxazoline group-containing monomer is polymerized and a polymer mixture is obtained, and even when the solid content of the oxazoline group-containing polymer in the polymer mixture is increased, viscosity is hardly increased, and in which productivity of the oxazoline group-containing polymer can be improved.

When the oxazoline group-containing polymer is produced by polymerizing a monomer component containing ≥40 mass% of the oxazoline group-containing monomer in the presence of a solvent mixture of an organic solvent with water, 1-4C monovalent aliphatic alcohol optionally having 1-3C alkoxy group is used as the organic solvent and the content of the organic solvent in the solvent mixture is adjusted to 10-65 mass%.