The present invention provides a rubber composition containing: (A) a rubber component containing from 90 to 100% by mass of at least one kind of diene rubber synthesized by solution polymerization and from 0 to 10% by mass of another kind of diene rubber; (B) a silica having a n-hexadecyltrimethylammonium bromide (CTAB) adsorption specific surface area of 180 m2/g or more measured according to a method described in ASTM D3765-92; (C) at least one silane coupling agent selected from a polysulfide compound and a thioester compound; and (D) a vulcanization accelerator, the rubber composition after vulcanization having an average aggregated aggregate area (nm2) of the silica of 1,700 or less, and thus provides a rubber composition that is improved in low-heat-generation property.