An apparatus, which is a refrigeration apparatus, comprising: - a refrigerant circuit filled with fluoropropene refrigerant of the formula C 3 H m F n wherein m and n are integers of 1-5 and satisfy the relationship of ( m + n )=6, or with refrigerant mixture containing the refrigerant, - a compressor including a fluid machine for compressing refrigerant, and an electric motor for driving the fluid machine and using refrigerant oil having - a volume resistivity of ≥ 10 10 Ω·m at 20°C, and - a surface tension of 0.02-0.04 N/m at 20°C; wherein the refrigerant is circulated in the circuit by the compressor to perform a refrigeration cycle; with the proviso that if the refrigerant is 1,2,3,3,3-pentafluoropropene, the refrigerant oil is not a pentaerythritol octanoate nonanoate mixed ester having - a C 8 /C 9 molar ratio of 1/1.1, - a molecular weight, calculated on the basis of the chemical structure of each compound constituting the base oil, of 669, - an acid value, measured in accordance with JIS K2501, of 0.00 mg KOH/g, - a hydroxyl value, measured in accordance with JIS K0070, of 3 > mg KOH/g - a kinematic viscosity at 100°C, measured using a glass capillary viscosimeter according to JIS K2283-1983, of 9.64, - a flash point, measured by C.O.C. method according to JIS K2265, of 260°C, - an ASTM Color of L0.5, - a surface tension of 34.7 mN/m, - a pH of extracted water of 6.4, - an ash content of < 0.1 mass%, and - a volume resistivity of 10 10 Ω·m. - a refrigerant circuit filled with fluoropropene refrigerant of the formula C 3 H m F n wherein m and n are integers of 1-5 and satisfy the relationship of ( m + n )=6, or with refrigerant mixture containing the refrigerant, - a compressor including a fluid machine for compressing refrigerant, and an electric motor for driving the fluid machine and using refrigerant oil having - a volume resistivity of ≥ 10 10 Ω·m at 20°C, and - a surface tension of 0.02-0.04 N/m at 20°C; - a volume resistivity of ≥ 10 10 Ω·m at 20°C, and - a surface tension of 0.02-0.04 N/m at 20°C; wherein the refrigerant is circulated in the circuit by the compressor to perform a refrigeration cycle; with the proviso that if the refrigerant is 1,2,3,3,3-pentafluoropropene, the refrigerant oil is not a pentaerythritol octanoate nonanoate mixed ester having - a C 8 /C 9 molar ratio of 1/1.1, - a molecular weight, calculated on the basis of the chemical structure of each compound constituting the base oil, of 669, - an acid value, measured in accordance with JIS K2501, of 0.00 mg KOH/g, - a hydroxyl value, measured in accordance with JIS K0070, of 3 > mg KOH/g - a kinematic viscosity at 100°C, measured using a glass capillary viscosimeter according to JIS K2283-1983, of 9.64, - a flash point, measured by C.O.C. method according to JIS K2265, of 260°C, - an ASTM Color of L0.5, - a surface tension of 34.7 mN/m, - a pH of extracted water of 6.4, - an ash content of < 0.1 mass%, and - a volume resistivity of 10 10 Ω·m. - a C 8 /C 9 molar ratio of 1/1.1, - a molecular weight, calculated on the basis of the chemical structure of each compound constituting the base oil, of 669, - an acid value, measured in accordance with JIS K2501, of 0.00 mg KOH/g, - a hydroxyl value, measured in accordance with JIS K0070, of 3 > mg KOH/g - a kinematic viscosity at 100°C, measured using a glass capillary viscosimeter according to JIS K2283-1983, of 9.64, - a flash point, measured by C.O.C. method according to JIS K2265, of 260°C, - an ASTM Color of L0.5, - a surface tension of 34.7 mN/m, - a pH of extracted water of 6.4, - an ash content of < 0.1 mass%, and - a volume resistivity of 10 10 Ω·m. <EOS>