Provided is a grease composition containing a base oil, a thickener, and an additive. The base oil contains a poly-α-olefin and has a kinematic viscosity of 20-60 mm2/s at 40° C. The thickener contains a urea compound produced by reacting a diisocyanate compound with a mixed amine containing an alicyclic amine and an aromatic amine. The additive contains a phosphorous acid ester, an ether compound, and an oxidized paraffin.