To provide a rubber composition for a tire which is suitably used as a material for forming a tread member of a studless tire etc., suppresses bleeding of an oil etc., compounded as a plasticizer, and has a small change in physical properties with time, particularly a small increasing rate in aging hardness, in order to retain constant properties of a tire for a long time.

This rubber composition for a tire includes, based on (A) 100 pts.wt. of a diene rubber, (B) 1-30 pts.wt. of a mixture of two kinds of polystyrene-polybutadiene-polystyrene triblock copolymers with 15-25 wt.% and 30-50 wt.% of total styrene contents at both terminals, (C) 30-90 pts.wt. of at least one of carbon black and silica, (D) 1-20 pts.wt. of a thermally expansible microcapsule including a material which evaporates or expands with heat to generate gas, and (E) a plasticizer in a weight ratio of 0.6-20 to the component (B).