A rubber composition for a tire having greatly shortened vulcanization time, good silica dispersibility and, after vulcanization, superior braking capability, abrasion resistance and low rolling resistance, comprising (A) 100 parts by weight of a conjugated diene-based rubber, (B) 90 to 150 parts by weight of a reinforcing filler containing silica, (C) 0 to 40 parts by weight of an oil, (D) 4 to 20% by weight, based upon the weight of the silica, a silane coupling agent having the formula (I): Y3Si—CnH2nA   (I) wherein Y indicates a C1 to C25 alkyl or alkoxyl group or a chloro group, the three Y's may be the same or different, n is an integer of 1 to 6, A is a mercapto group or SmZ group, where Z is the group: and m is an integer of 1 to 6) (E) sulfur, and (F) 0.05 to 5 parts by weight of a thiuram disulfide-based vulcanization accelerator having the formula (II): wherein R5, R6, R7 and R8 are independently hydrocarbon groups having 2 to 18 carbon atoms, is provided.