Refrigerator oil, and working fluid composition for refrigerator

A working fluid composition for a refrigerating machine comprising:

• a refrigerant consisting of
• difluoromethane (R32),
• pentafluoroethane (R125), and
• trifluoroiodomethane;
• and
• a refrigerating machine oil comprising:
• an ester-based base oil comprising a polyol ester of a polyhydric alcohol comprising pentaerythritol and a fatty acid having 4 to 9 carbon atoms,
• at least one epoxy compound selected from an alkyl glycidyl ether represented by the following formula (1) and an aryl glycidyl ether represented by the following formula (2):
• wherein
• R1 represents an alkyl group having 5 to 10 carbon atoms and
• R2 represents an aryl group having 6 to 12 carbon atoms;
• and
• a phenol-based antioxidant,
• wherein a content of the ester-based base oil is 90% by mass or more, a content of the epoxy compound is 0.7% by mass or more and 5.0% by mass or less, and a content of the phenol-based antioxidant is 0.3% by mass or more and 3% by mass or less, based on a total amount of the refrigerating machine oil, and
• wherein a ratio of (sum of content of R32 and content of trifluoroiodomethane)/(content of R125) is 50/50 to 95/5.