Provided is a refrigerating machine oil composition for a mixed refrigerant comprising difluoromethane, the composition comprising a polymer (A) below and an ester (B) of polyhydric alcohol(s) with aliphatic monocarboxylic acid(s).The polymer (A): a polymer which is obtained by polymerizing monomer(s) consisting of at least one monomer of monosubstituted ethylenes and disubstituted ethylenes, and in which a ratio of a monomer represented by the following general formula (I): wherein R1 represents an alkyl group having 1 to 14 carbon atoms, R2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and the sum of carbon numbers in R1 and R2 is 2 to 14, is 75 to 100% by mass based on a total mass of monomers constituting the polymer.