PURPOSE: To reduce weight and to enhance both air-pressure holding performance and durability of a pneumatic tire of tubeless structure by arranging an inner liner layer consisting of a copolymer layer of vinylidene chloride at the inside of a crude rubber tire formed with unvulcanized rubber and then vulcanizing/forming the tire.

CONSTITUTION: A spray gun 2 is arranged, facing the internal surface of a crude rubber tire 1, while an emulsion supply pipe 3, which concurrently is a supporting member, is supported by a driving/supporting part 4 in a freely rotatable/slidable manner. Emulsion of copolymer of vinylidende chloride, whose viscosity has been adjusted in advance, is automatically sprayed/applied within a splash preventing box 5, while changing the direction of spray in accordance with a spary program, which has been adjusted according to the size of the tire. Since the gas permeability of the rubber thus produced is very small compared with conventional butyl rubber halogenide, and the inner liner layer can be thinned, thereby the weight of the tire can be reduced. In addition, since variation in the moisture permeability against the change of relative temperature is small and the moisture permeability is low, intrusion of moisture can be prevented and the durability can be enhanced.