Abstract: A composition that is used as a lubricating oil includes: a lubricant base oil including a mineral base oil or no mineral base oil, a poly-?-olefin base oil or no poly-?-olefin base oil, and at least one ester base oil, wherein the ester base oil is an ester of at least one saturated or unsaturated fatty acid having no branched chain structure, and at least one alcohol, and the content of the ester base oil is no less than 15 mass % based on total mass of the lubricant base oil, the ester base oil including no fatty acid having a branched chain structure, and the kinematic viscosity of the composition at 40° C. is 2.0 to 23.0 mm2/s.