A rubber composition contains at least: a diene rubber, a silica, a silane coupling agent having a mercapto group, a plasticizer, and an oil and/or a resin; from 50 to 200 parts by mass of the silica per 100 parts by mass of the diene rubber and from 2 to 20 mass % of the silane coupling agent having a mercapto group relative to the amount of the silica being blended; and a total amount of the plasticizer and the oil and/or the resin being 60 parts by mass or greater per 100 parts by mass of the diene rubber.