PURPOSE: To obtain a lubricating oil composition having no reduced basicity and excellent stability by mixing a lubricating base oil, an over-based alkaline earth metal salt of an aromatic carboxylic acid and a stabilizer.

CONSTITUTION: The lubricating oil composition is produced by mixing (A) preferably a lubricating base oil of hydrocarbons with a viscosity of 3 to 35 cst (100°C), (B) 0.5 to 20 wt.% of an over-based alkaline earth metal salt of an aromatic carboxylic acid (e.g. Mg salt and/or Ca salt of alkyl salicylate) containing a benzene ring or a naphthalene ring and an oil-soluble group of 8c or more and (C) 0.005 to 2.0 wt.% of a stabilizer (e.g. polyethoxylated 8-15C alkanol containing 4 to 10 ethoxy groups), a polyalkoxylated alcohol having a molecular wt. from 150 to 1500, preferably from 350 to 1000, selected from polyalkoxylated (cyclic) aliphatic, polyalkoxylated heterocyclic-, and polyalkoxylated aromatic alcohols.