An airbag apparatus includes: a main body having an air bag; and a support member to which the main body is attached so as to arrange the airbag apparatus in a door or a side wall of a vehicle. The support member is attached to the vehicle body via a pair of bracket members which are positioned in the vicinity of both ends of the support member and are easily deformable when an impact is applied. The support member has a fastening part between the bracket members, and is fastened to the vehicle body via the fastening part. Before the airbag apparatus is attached to the vehicle body, the main body and the support member may be coupled with each other using at least one of a common fastening of them to the bracket members and a mutual coupling between them at the position of the fastening part.
