Air permeation resistant film and pneumatic tire

An air permeation resistant film consisting essentially of:

• (A) a thermoplastic polyester elastomer which is a block copolymer containing a hard segment and a soft segment, and has a melting point of from 180 to 230° C., and (B) at least one rubber, in a mass ratio (A)/(B) of from 90/10 to 40/60,
• wherein the component (A) and the component (B) are melt-kneaded to perform dynamic crosslink, thereby forming a continuous phase composed of the component (A) and a dispersed phase composed of the component (B),
• wherein the hard segment comprises polybutylene terephthalate,
• wherein the soft segment comprises aliphatic polycarbonate,
• the film has an air permeation coefficient at 80° C. of 5×1013 fm2/Pa·s or less and Young's modulus of 120 MPa or less,
• wherein a number average molecular weight of aliphatic polycarbonate diol, which is a raw material of the aliphatic polycarbonate, is from 3,000 to 60,000.