A rubber composition comprises from 2 to 50 parts by weight of an aromatic modified terpene resin having a softening point of ≧100° C., and two types of silica, a silica X and a silica Y, at a total quantity of 60 to 130 parts by weight relative to 100 parts by weight of a diene rubber containing from 5 to 50 weight % of a modified S-SBR having a vinyl content of not lower than 60 weight %. A functional group in the modified S-SBR reacts with a silanol group, a proportion of silica relative to the total quantity of a reinforcing filler containing the silica and carbon black is not lower than 85 weight %, a nitrogen specific surface area of the silica X is not lower than 140 m2/g, and a nitrogen specific surface area of the silica Y is not lower than 100 m2/g but lower than 140 m2/g.