To provide a rubber composition for a tire increasing the interaction between rubber fillers, low in heat buildup, and able to raise the vulcanization speed.A rubber composition for a tire containing 100 parts by weight of (A) a sulfur-vulcanizable diene-based rubber, (B) 0.1 to 1 part by weight of a 4,4′-oxybis(benzenesulfonylazide) and (C) a vulcanization type compounding agent, wherein the ingredients (A) and (B) are mixed at the time of a first mixing step before the compounding of the ingredient (C).