| abstract |
Provided is a lubricating oil composition containing (A) 70 mass% or more and 95 mass% or less of a poly-±-olefin base oil, (B) 5 mass% or more and 20 mass% or less of an ester-based base oil, and (C) an ester-based defoaming agent, the poly-±-olefin base oil (A) being a polymer of an ±-olefin having 8 to 12 carbon atoms. The lubricating oil composition is able to keep excellent defoaming performance over a long period of time and is suitable as a step-up gear oil composition for wind power generation. |