LUBRICATING OIL COMPOSITION AND AUTOMOTIVE TRANSMISSION OIL USING SAME

An object of the present invention is to provide a lubricating oil composition having a low viscosity and an extremely high viscosity index as well as an excellent shearing stability. The present invention relates to a lubricating oil composition including the following components (A) to (C): (A) a low-viscosity synthetic oil including a compound containing an ether bond in a molecule thereof and having a kinematic viscosity of less than 10 mm 2 /s as measured at 40°C, in which a ratio of the number of oxygen atoms to the number of carbon atoms as constituents of the compound (O/C ratio) and the kinematic viscosity (mm 2 /s) of the compound as measured at 40°C satisfy the following formula (1): Kinematic Viscosity at 40 ¢ °C ‰¤ 12 - O / C ratio × 30 (B) a high-viscosity synthetic oil as a hydrocarbon-based synthetic oil having a kinematic viscosity of 40 mm 2 /s or more as measured at 100°C which includes at least one compound selected from the group consisting of an ±-olefin oligomer or a hydrogenated product of the ±-olefin oligomer, and an ethylene-propylene co-oligomer; and (C) a polymethacrylate having a weight-average molecular weight of 50,000 or less.