An industrial oil composition contains a mineral or a synthetic oil as a base oil, and a neutral phosphite ester derivative represented by the following formula (B) and a 2,6-di-t-butylphenol derivative represented by the following formula (C) as antioxidants. In the formula (B), Rb21 to Rb24 each independently represent an aliphatic hydrocarbon group of 10 to 16 carbon atoms. In the formula (C), Rc1 represents a straight-chain or a branched alkyl group of 1 to 12 carbon atoms.