| abstract |
The lubricating base oil of the invention is characterized by satisfying at least one of the following conditions (a) or (b).n (a) A saturated compound content of 95% by mass or greater, and a proportion of 0.1-10% by mass of cyclic saturated compounds among the saturated compounds. (b) The condition represented by the following formula (1).n n1.435≦ n 20 −0.002× kv 100≦1.450 (1)n nwherein n 20 represents the refractive index of the lubricating base oil at 20° C., and kv100 represents the kinematic viscosity (mm 2 /s) of the lubricating base oil at 100° C. |