A composition suitable as lubricating oil for refrigerator, comprising: (i) a base oil which is at least one compound selected from polyvinyl ether and an ether-base compound of formula R a -[(OR b) n - -(OR C)k] x -R d wherein R a and R d each are H, C 1-10 -alkyl, C 2-10 -acyl or a C 1-10 -hydrocarbon group having 2-6 bonding sites; R b and R c each are C 2-4 -alkylene; k is an integer of 0-20; n is an integer of 0-20; x is an integer of 1-6; and is a polymerization site containing ≥ 3 monomer units each individually being a unit of formula wherein R 4 -R 6 each independently are H or a C 1-8 -hydrocarbon group, R 7 each individually is a divalent C 1-10 -hydrocarbon group or divalent ether-bonded oxygen-containing C 2-20 -hydrocarbon group; R 8 is H or a C 1-20 -hydrocarbon group; m is a number of an average value of 0-10; and if in formula k and n both are 0, m in formula is an integer of ≥ 1; and (ii) added to the base oil, 0.1-30 mass-% of an acid scavenger, based on the total amount of the composition, which is a polypropylene glycol diglycidyl ether of formula: R 1 -[(OR 2) e -OR 3] f wherein e is an integer of 5-40, f is 1, R 1 is glycidyl, R 2 is C 3 -alkylene, and R 3 is glycidyl; and (iii) a refrigerant containing at least one unsaturated fluorine-containing organic compound of formula: C p O q F r R s wherein R is H, p is an integer of 2-6, q is 0, r is an integer of 1-12 and s is an integer of 0-11; with the proviso that at least one unsaturated carbon-carbon bonding is present in the molecule; and optionally a saturated fluorohydrocarbon compound. (i) a base oil which is at least one compound selected from polyvinyl ether and an ether-base compound of formula R a -[(OR b) n - -(OR C)k] x -R d wherein R a and R d each are H, C 1-10 -alkyl, C 2-10 -acyl or a C 1-10 -hydrocarbon group having 2-6 bonding sites; R b and R c each are C 2-4 -alkylene; k is an integer of 0-20; n is an integer of 0-20; x is an integer of 1-6; and is a polymerization site containing ≥ 3 monomer units each individually being a unit of formula wherein R 4 -R 6 each independently are H or a C 1-8 -hydrocarbon group, R 7 each individually is a divalent C 1-10 -hydrocarbon group or divalent ether-bonded oxygen-containing C 2-20 -hydrocarbon group; R 8 is H or a C 1-20 -hydrocarbon group; m is a number of an average value of 0-10; and if in formula k and n both are 0, m in formula is an integer of ≥ 1; and R a and R d each are H, C 1-10 -alkyl, C 2-10 -acyl or a C 1-10 -hydrocarbon group having 2-6 bonding sites; R b and R c each are C 2-4 -alkylene; k is an integer of 0-20; n is an integer of 0-20; x is an integer of 1-6; and is a polymerization site containing ≥ 3 monomer units each individually being a unit of formula R 4 -R 6 each independently are H or a C 1-8 -hydrocarbon group, R 7 each individually is a divalent C 1-10 -hydrocarbon group or divalent ether-bonded oxygen-containing C 2-20 -hydrocarbon group; R 8 is H or a C 1-20 -hydrocarbon group; m is a number of an average value of 0-10; and if in formula k and n both are 0, m in formula is an integer of ≥ 1; and (ii) added to the base oil, 0.1-30 mass-% of an acid scavenger, based on the total amount of the composition, which is a polypropylene glycol diglycidyl ether of formula: R 1 -[(OR 2) e -OR 3] f wherein e is an integer of 5-40, f is 1, R 1 is glycidyl, R 2 is C 3 -alkylene, and R 3 is glycidyl; and e is an integer of 5-40, f is 1, R 1 is glycidyl, R 2 is C 3 -alkylene, and R 3 is glycidyl; and (iii) a refrigerant containing at least one unsaturated fluorine-containing organic compound of formula: C p O q F r R s wherein R is H, p is an integer of 2-6, q is 0, r is an integer of 1-12 and s is an integer of 0-11; with the proviso that at least one unsaturated carbon-carbon bonding is present in the molecule; and optionally a saturated fluorohydrocarbon compound. R is H, p is an integer of 2-6, q is 0, r is an integer of 1-12 and s is an integer of 0-11;