Abstract: A dispersion improved carbon black compounded rubber composition comprises a rubber component and a reinforcing carbon black in an amount of from 30 to 150 parts by weight with respect to 100 parts by weight of the rubber component. The rubber component is selected from a group consisting of a natural rubber, synthetic isoprene rubber and a mixture thereof, or a blend of this rubber component with a diene base synthetic rubber other than this rubber component. The reinforcing carbon black has a specific surface area of from 70 to 200 m.sup.2 /g when measured by a nitrogen adsorption method and a DBP value of from 80 to 130 ml/100 g, and is obtained by introducing mainly phenolic hydroxide groups into the surface of the carbon black through plasma treatment at low temperatures or by introducing carboxyl groups and the phenolic hydroxide groups thereinto through plasma treating at low temperatures and neutralizing the thus introduced acid groups.