Grease composition for rolling bearings and rolling bearing

A grease composition for rolling bearings, comprising, with respect to the total mass of the composition, 75 to 90 mass % of a base oil, 8 to 20 mass % of a urea thickener and 0.1 to 5 mass% of a metal deactivator, wherein;

• the base oil is a mixture of a paraffinic mineral oil and poly-alpha-olefin at a mass ratio of 50/50 to 99/1, the base oil having an aniline point of 130° C. or more and having a kinematic viscosity at 40° C. of 15 to 200 mm2/s,
• the urea thickener is at least one selected from the group consisting of diurea compounds represented by formulas (2) to (4)
• R4—NHCONH—R2—NHCONH—R4 (2)
• R4—NHCONH—R2—NHCONH—R5 (3)
• R5—NHCONH—R2—NHCONH—R5 (4)
• wherein R2 represents a bivalent aromatic hydrocarbon group having 6 to 15 carbon atoms;
• R4 represents a C10-26 alkyl group, and R5 represents a C5-7cycloalkyl group and the ratio of the number of moles of R4 to the total number of moles of R4 and R5, expressed by [100 x (the number of moles of R4) / (the number of moles of R4+the number of moles of R5)] is in the range of 50 to 90 mol % in the urea thickener, and
• the metal deactivator is at least one selected from the group consisting of 1-[N,N-bis(2-ethylhexyl)aminomethyl]-4-methyl-benzotriazole, thiadiazole, 2-mercaptothiadiazole, 2,5-bis(alkyldithio)-1,3,4-thiadiazole, 2-mercaptobenzimidazole and 2-(decyldithio)-benzimidazole.