To prevent a sewn part between a tether belt and an airbag for regulating the airbag for its expansion and development in a specified shape from being broken by high-pressure gas, and to reduce the size/weight of an airbag device.

In an airbag 5 expanded and developed by high-pressure gas jetted out from an inflator 4 by shocks at the time of clashing to protect an occupant from the shocks of the clashing, at least one tether belt 7 is provided to regulate the airbag 5 to expand and develop in a specified shape, a fixed part between the base cloth of the airbag 5 and the tether belt 7 is sewn by the two rows of sewing parts 8 including first and second sewing parts 81 and 82 disposed side by side in the longitudinal direction of the tether belt 7, and the second sewing part 82 positioned toward the center side than the first sewing part 81 positioned in the end side of the tether belt 7 is broken or loosened against a tensile force added to the tether belt 7 during the expansion of the airbag 5.