To provide a diene-based rubber composition giving a molded article having a high elastic modulus and excellent in heat aging resistance, chipping resistance and cutting resistance, while suppressing an increase of heating value.

The diene-based rubber composition is obtained by blending (a) 100 pts.wt. of diene-based rubber, (b) 3-8 pts.wt. of zinc monomethacrylate, (c) 30 pts.wt. of a carbon black, (d) 2-30 pts.wt. of silica, and (e) 0.5-5 pts.wt. of at least one selected from modified gum rosin, p-octylphenol resin, 1,3-pentadiene resin and dicyclopentadiene resin, wherein the carbon black and silica are blended in a total amount of 40-60 pts.wt. The diene-based rubber composition is effectively used as a forming material of at least one of a cap tread and a base tread of a tire.