Provided is a rubber composition for tires, comprising: diene rubber contained in the quantity of 100 parts by mass; silica contained in the quantity of 60-200 parts by mass; polysiloxane represented by averaged compositional formula (1), and contained in the quantity of 1-20 mass% with respect to the quantity of silica; and a thiuram disulfide vulcanization accelerator contained in the quantity of 0.05-3.0 parts by mass. Formula (1): (A)a(B)b(C)c(D)d(R1)eSiO(4-2a-b-c-d-e)/2 (In the formula, A represents a bivalent organic group containing a sulfide group, B represents a C5-10 monovalent hydrocarbon group, C represents a hydrolyzable group, D represents an organic group containing a mercapto group, R1 represents a C1-4 monovalent hydrocarbon group, and a-e satisfy the conditional formulae 0≤a<1, 0≤b<1, 0<c<3, 0<d<1, 0≤e<2, and 0<2a+b+c+d+e<4, with the caveat that either a or b is not 0.) Also provided is a pneumatic tire using said rubber composition for tires in tire tread.