To provide a grease composition excellent in flaking resistance, seizure resistance, low abrasion properties and the like.

The grease composition comprises a lubricating base oil and, incorporated therewith, (A) 2-30 mass% of a urea-based thickening agent, (B) 0.1-20 mass% of a dihydrocarbyl polysulfide and/or sulfurized oils and fats, (C) 0.05-10 mass% of perbasic magnesium sulfonate having a total base value of 100-500 mg KOH/g, and (D) at least one selected from the group consisting of a solid lubricating agent, an extreme pressure agent comprised of molybdenum dithiocarbamate and molybdenum dithiophosphate, an antioxidant, an oily agent, a rust preventive and a viscosity index improving agent, each based on the total amount of the composition, and is useful as a grease for constant speed gears, speed change gears, iron-manufacturing equipment, and the like.

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