To provide a white rubber composition used in the decoration of a side wall of a tire and capable of simultaneously satisfying endurance and productivity.

This white rubber composition is obtained by adding the following components (A) to (D) to 100 pts.wt. rubber component composed of 20-80 wt.% bromobuthyl rubber and the balance of other diene rubber: (A): 20-150 pts.wt. calcium carbonate as a white filler, (B): 1-10 pts.wt. sulfur, (C): 0.1-5 pts.wt. dithiophosphate or phosphoarylpolysulfide as a curing accelerator and (D) 0.1-5 pts.wt. diphenylguanidine.