A refrigerator oil composition contains base oil and polyalkylene glycol (PAG) block copolymer. The PAG block polymer is represented by the following formula (1). €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒR 1 [(OR 2 ) m (OE) n OR 3 ] 1 €ƒ€ƒ€ƒ€ƒ€ƒ(1) In the formula: R 1 represents a hydrocarbon residue having 1 to 10 carbon atoms; R 2 represents an alkenyl group having 3 to 6 carbon atoms; E represents an ethylene group; R 3 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; m and n each represent a positive integer, a ratio of m to n (m/n) being 99/1 to 50/50; and I represents an integer in a range of 1 to 100.