Provided are: a rubber composition for a tire base rubber, including: (A) a rubber component including an amine-based functional group modified polybutadiene rubber; and (B) silica having a cetyltrimethylammonium bromide (CTAB) adsorption specific surface area of 50 to 120 (m2/g) and having a nitrogen adsorption specific surface area (N2SA), which is determined by a BET method, of 70 to 140 m2/g, in which the silica is blended in an amount of 20 to 120 parts by mass with respect to 100 parts by mass of the rubber component, the rubber composition being capable of providing a pneumatic tire which is excellent in fracture property and can have greatly reduced rolling resistance; and a pneumatic tire having the above-mentioned characteristics made using the rubber composition as a base rubber.