To provide a diene-based rubber composition which is suitably used as a vulcanization molding material and so on for forming a lower hard bead filler having an improved balance of high rigidity, heat aging resistance, and an elasticity modulus while suppressing increase in the heat release value, and having improved durability.

The diene-based rubber composition is obtained by compounding: (b) zinc monomethacrylate of 8-14 pts.wt.; (c) carbon black of 60-80 pts.wt.; and (d) at least one of a para-octylphenol resin, a modified gum rodin, a 1,3-pentadiene resin, and a dicyclopentadiene resin of 0.5-8 pts.wt., based on 100 pts.wt (a) the diene-based rubber.