Rubber composition for inner liner and pneumatic tire

The present invention provides a rubber composition for an inner liner, which can achieve both excellent low heat build-up and high flex crack growth resistance while having processability excellent enough to eliminate the need for mastication, and further has good air impermeability, and also provides a pneumatic tire produced using the rubber composition. The present invention relates to a rubber composition for an inner liner, including: a rubber component that contains a modified natural rubber with a phosphorus content of 200 ppm or less, and carbon black and/or a white filler.