TREAD RUBBER COMPOSITION AND PNEUMATIC TIRE

Provided are tread rubber compositions and pneumatic tires which are excellent in abrasion resistance. Included is a tread rubber composition containing, based on 100% by mass of a rubber component therein, 10% by mass or more of styrene-butadiene rubber and 10% by mass or more of polybutadiene rubber, and having an absolute value of change in hardness before and after heat aging, |ΔHs|, satisfying the following relationship (1) and an absolute value of change in Swell before and after heat aging, |ΔSwell|, satisfying the following relationship (2): Δ Hs ≤ 3.0 Δ Swell ≤ 20 %