An airbag device includes: an airbag having an exhaust hole capable of discharging a part of the inflation gas introduced therein upon opening; and an opening/closing control device capable of controlling opening/closing of the exhaust hole. The airbag has: a flexible bag main body; a discharge part having the exhaust hole; and a coupling member. Peripheral edges of a pair of peripheral wall constituting parts are joined to form the bag main body and the discharge part. Discharge part forming portions, which constitute the discharge part, partially protrude in the peripheral wall constituting parts, respectively. An opening, which constitutes the exhaust hole, is formed in a region, which is closer to a tip end-side of the discharge part than seal parts crimped to each other when the discharge part is pulled into the bag main body.