To obtain the subject oil composition capable of suppressing deterioration of refrigerating machine itself, preventing occurrence of metal corrosion and copper plating phenomenon and capable of stably using by using a specific base oil and keeping water content of the base oil in a constant amount.

This refrigerating machine oil composition comprises a base oil consisting essentially of oxygen-containing organic compound and having 5-50 mm2/s kinematic viscosity, ≥60 viscosity index and ≤300 ppm, preferably ≤250 ppm water content. Further, the above oxygen-containing organic compound is preferably a polyoxyalkylene glycol of the formula R1-[(OR2)m-OR3]n [R1 is H, a 1-10C alkyl or the like; R2 is 2-4C alkylene; R3 is H, a 1-10C alkyl or a 2-10C acyl; (n) is 1-6; (m) is a number in which average value of (m×n) is 6-80], a polyvinyl ether of the formula [R16 to R18 are each H, a 1-8C alkyl or the like; R19 is a 1-10C divalent hydrocarbon; R20 is a 1-20C hydrocarbon; (k) is average 0-10] or the like.