A grease composition may contain a base oil (A) and a urea-based thickener (B). Particles containing the urea-based thickener (B) in the grease composition may satisfy requirement (I). The base oil (A) may be a mixed base oil containing a high-viscosity base oil (A1) having a kinematic viscosity at 40° C. of 250 mm2/s to 550 mm2/s, a low-viscosity base oil (A2) having a kinematic viscosity at 40° C. of 5.0 mm2/s to 110 mm2/s, and an ultra-high viscosity hydrocarbon-based synthetic oil (A3) having a number average molecular weight (Mn) of 2,500 to 4,500 and a kinematic viscosity at 40° C. of 25,000 mm2/s to 50,000 mm2/s. The base oil (A) may have a kinematic viscosity at 40° C. of 25 mm2/s to 105 mm2/s and a viscosity index of 120 or more. Both low-temperature characteristics and a lubricating life can be achieved.