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.