A rubber composition in which from 80 to 150 parts by weight of carbon black having a nitrogen adsorption specific surface area of from 200 to 400 m2/g is compounded per 100 parts by weight of styrene-butadiene rubber including from 60% to 100% by weight of solution-polymerized styrene-butadiene rubber S-SBR1 and from 40% to 0% by weight of solution-polymerized styrene-butadiene rubber S-SBR2 to result in a total of 100% by weight, the styrene quantity of the S-SBR1 being from 30% to 38% by weight, the vinyl quantity of the S-SBR1 being from 60% to 80% by weight, the glass transition temperature of the S-SBR1 being from −20° C. to −5° C., the weight-average molecular weight of the S-SBR1 being from 1,000,000 to 1,800,000, the glass transition temperature of the S-SBR2 being not less than −30° C. and less than −20° C., and the weight-average molecular weight of the S-SBR2 being from 1,000,000 to 1,800,000.