To obtain an air bag enhancing in folding properties comprising plain fabrics or a structure of Panama cloth constructed so that the practical air permeability does not increases when stress is added to the warp and weft direction.

This air bag is obtained by using fabrics composed of non-coated fabrics weaved into the plain or the Panama structure using polyester or nylon preferably, nylon 66 fibers and exhibits air permeability not exceeding 1 ft3/ min.ft2 under the pressure descent of 124 pascal crossing the fabric in a state practically free from tension on the fabric, and exhibits air permeability not exceeding 5 ft3/min.ft2 preferably not exceeding 4 ft3/min.ft2 more preferably not exceeding 3 ft3/min.ft2 more preferably not exceeding 2 ft3/min.ft2 under the pressure descent of 124 pascal crossing the fabric under practically equal two axial tension up to 150 lb/in loaded on the weft and warp direction.