To provide a rubber composition for tires enhancing the reaction rate of silica, alkoxyalkylsilane and a silica coupling agent and improving rolling resistance, aging resistance and scorch resistance, and a pneumatic tire using it.

In the rubber composition for tires, 40 pts.mass or more of silica and 100 pts.mass of a diene-based rubber are formulated, 2-10 mass% of one kind or more of alkoxyalkylsilane selected from dialkoxyalkylsilane and trialkoxyalkylsilane is formulated relative to the amount of silica, 0.5-3 pts.mass of a carboxylic acid amine salt is formulated, and a silane coupling agent is also formulated. In the pneumatic tire, the rubber composition for tires is used for cap treads.