To provide a gear oil composition, being excellent in power saving and low-temperature fluidity, and having a good extreme-pressure property.

The gear oil composition is obtained by blending an olefin-based viscosity index-improving agent including a copolymer of ethylene and a monomer other than ethylene and an extreme pressure agent containing sulfur with a hydrocarbon-based base oil (excluding a poly--olefin base oil) for a lubricating oil having %CN of 25 or less and %CA of 1.5 or less by a ring analysis, the blending amount of the extreme pressure agent containing sulfur being 0.1-10 mass% based on the total amount of the composition, and a kinematic viscosity of the composition at 40C being 30-2,000 mm2/s.