To provide a rubber composition having excellent wet grip performance while maintaining low heat build-up characteristics without lowering processability, abrasion resistance and rolling resistance. The rubber composition of the present invention comprises, based on 100 parts by weight of a diene rubber (A), 5 to 150 parts by weight of particular inorganic filler (B), 5 to 150 parts by weight of carbon black (C) having a nitrogen adsorption specific surface area of 70 to 300 m.sup.2/g, and 1 to 20 % by weight of a silane coupling agent (D). The pneumatic tire of the present invention is obtained by using the rubber composition for the tread rubber.