A rubber composition for tire tread or a rubber composition for tire sidewall, comprising one or more rubber components, and a composite powder which comprises a persimmon fruit extract and sodium carbonate and which is in an amount of 1.0 to 10 parts by mass when a total amount of the rubber component(s) is regarded as 100 parts by mass. In the rubber compositions, it is preferable that in the composite powder, a ratio by mass of the persimmon fruit extract to the sodium carbonate is from 1:1 to 5:1. Moreover, in the rubber compositions, it is preferable that when a total amount of the rubber component(s) is regarded as 100 parts by mass, an effective component amount of the persimmon fruit extract in the composite powder is from 0.01 to 8.0 parts by mass.