| abstract |
Provided is a lubricating oil composition which is excellent in thermal stability and chemical stability while allowing detection of a leakage point of a lubricating oil composition or the like by a fluorescent agent. The fused ring comprises a base oil (A) and a fluorescent fused ring compound (B) having no fused nitrogen, oxygen and sulfur and having three or more fused rings in the molecule, A lubricating oil composition comprising the compound of formula (B) in an amount of 0.001 to 1.0% by mass based on the total amount of the lubricating oil composition. |