A lubricating oil composition according to the present invention is used in an internal combustion engine. The internal combustion engine uses a fuel that contains at least one fat and oil selected from a group consisting of natural fat and oil, hydrotreated natural fat and oil, transesterified natural fat and oil and hydrotreated transesterified natural fat and oil. The lubricating oil composition contains a component (A) that is an alkaline earth metal-based detergent. The component (A) is contained by a content of more than 0.35 mass % and 2 mass % or less of the total amount of the composition in terms of alkaline earth metal.