PURPOSE: To increase the strength of a joint part to a value higher than that of a conventional type by a method wherein the outer periphery of a double hollow weave part for a circular fluid introduction bag part is closed by a joint part formed by weave texture, and the joint is formed such that a joined singlet texture zone and a double hollow weave zone are formed in order.

CONSTITUTION: An air bag 1 is formed such that joint parts 4, 5, and 6 are circularly formed to the outer peripheries of a fabric 2 on the surface and a fabric 3 on the back side. The joint parts are formed such that a joined singlet texture zone 4, a double hollow weave zone 5, and a joined singlet texture zone 6 are formed annularly, in order, from the inner side. This constitution increases the strength of the joint part to a value higher than that of a conventional type, and decreases a given amount of threads being enough for provision of the given strength of the joint part.