A rubber composition for tire bead insulation contains a diene rubber, a nitrone compound having a carboxy group, a carbon black and a white filler. The diene rubber contains a natural rubber and a styrene-butadiene rubber and the mass ratio of the contents of the natural rubber and the butadiene rubber is from 50:50 to 90:10. The content of the nitrone compound is from 0.1 to 10 parts by mass (PBM) per 100 PBM of total content of the diene rubber and the nitrone compound. The content of the carbon black is not less than 70 PBM per 100 PBM of the total above. The content of the white filler is not less than 20 PBM per 100 PBM of the total above. The total content of the carbon black and the white filler is from 90 to 180 PBM per 100 PBM of the total above.