An airbag apparatus includes a tether interconnecting a front fabric of an airbag and an inflator to retain the airbag in an occupant restraining deployed configuration. Back fabric of the airbag has an opening portion for discharging gas, ejected from the inflator into the airbag, to outside the airbag. A fabric member that has an outward peripheral portion greater in size than the opening portion of the back fabric is mounted to the inflator, and the fabric member is disposed within the airbag.