A synthetic lubricating oil comprising as a base oil at least one kind of a carbonic acid ester selected from the group consisting of:
[I] a carbonic acid ester represented by the general formula (1)
wherein R 1 and R 2 are each an alkyl or dihydric alcohol residue, R 3 is an alkylene, and a is 0 - 30, [II] a carbonic acid ester represented by the general formula (2) wherein X 1 is -H or
R 4- R 6 are each an alkyl, cycloalkyl or neopentyl type polyol residue, R 7 is an alkyl, b is 1 or 2, c is 0 or 1 (b + c = 2), d is 0 - 30, and e is 1 - 3, and [III] a carbonic acid ester of which alcohol moieties are (A) a monohydric alcohol, (B) a dihydric alcohol, and (C) a neopentyl type polyol or dimer or trimer thereof.