A lubricating oil composition including 100 mass parts of (A) an ester compound, 0.05 to 1.5 mass parts of (B) an amine salt of an acidic phosphoric ester and 0.01 to 0.50 mass parts of (C) a monoesterified compound, wherein (A) the ester compound is an ester compound of trimethylolpropane, a straight-chain saturated fatty acid having a carbon number of 8 to 10 and adipic acid; (B) the amine salt is an amine salt of an acidic phosphoric ester; and (C) the monoesterified compound is a monoesterified compound of an alkane diol having a carbon number of 3 to 8 and of succinic acid having an alkyl group having a carbon number of 8 to 18 or an alkenyl group having a carbon number of 8 to 18.