To provide an air filling device for a tubeless tire capable of safely and efficiently performing air filling by preventing deformation of the tire and leakage of air in the air filling device for the tubeless tire for a large size vehicle comprising a tire conveying means and an air filling means.

The air filling device for the tubeless tire comprises the tire conveying means 2 comprising a pair of belt conveyors 2a, 2a traveling in parallel with an interval; an air feeding means 3 for feeding air to the tire T while pressing an upper surface part of the tire T; and a tire supporting means 4 for supporting the tire T or a wheel W at filling of air. The tire supporting means 4 comprises a base plate 4a capable of being separated/moved to left and right sides; and a wheel supporting part 4b at a central part of the base plate 4a. The wheel supporting part 4b is interposed between the pair of belt conveyors 2a, 2a and liftably supports a center cone 4b1 engageable with a central hole of the wheel W.