A grease composition includes a base oil and a thickener. The base oil includes a hydrocarbon-based synthetic oil at 40 mass % or more, and a component A at 20 mass % to 70 mass %, the component A having a kinematic viscosity of 70 mm2/s or less at 40 degrees C. A kinematic viscosity of the base oil is in a range from 200 mm2/s to 2000 mm2/s at 40 degrees C. A worked penetration of the grease composition is in a range from 220 to 350.