The present invention provides a lubricating oil composition than can keep the metal-to-metal friction coefficient high and is excellent in anti-seizure properties. The lubricating oil composition comprises a base oil and on the basis of the total mass of the composition (A) 0.05 percent by mass or more of a polysulfide, (B) 0.05 percent by mass or more of thiadiazole and (C) 0.1 percent by mass or more of a phosphorus-containing additive, and containing sulfur in an amount of 0.2 percent by mass or more on the basis of sulfur and phosphorus in an amount of 0.2 percent by mass or less on the basis of phosphorus, the ratio of the sulfur basis percent by mass/the phosphorus basis percent by mass (S/P) being from 3.0 to 5.0.