The present technology is a rubber composition for a tire comprising: a diene rubber; and a composite silica comprising a block copolymer and silica, the block copolymer comprising a first block obtained by polymerizing a first monomer containing at least a (meth)acrylate having a hydroxyl group and a second block obtained by polymerizing at least one type of a second monomer selected from the group consisting of styrene, derivatives thereof, and isoprene; the composite silica being produced in an organic solvent in the presence of the silica; and an amount of the composite silica being from 10 to 200 parts by mass per 100 parts by mass of the diene rubber; and a pneumatic tire using the same.