AIRBAG DEVICE

An airbag device includes an airbag formed with a discharge portion. The discharge portion includes: an opening portion; a tack portion around the opening portion; and a regulating belt portion disposed on a peripheral edge of the opening portion to regulate opening and closing of the opening portion. When the inflation of the airbag is completed, the tack portion is maintained in a folded state by the regulating belt portion due to tension acting on the regulation belt portion, so that a closed state of the opening portion is capable of being maintained, and when the tension does not act on the regulating belt portion, the folded state is released and the opening portion is brought into an open state.