An airbag device includes an airbag, an inflator and an attachment base. The airbag includes a body portion, and an inflow port portion, into which the distal end side of the inflator is inserted. The attachment base includes a holding plate portion including a pressing portion and a support portion that are provided at positions displaced around an axial center of the inflator so as to surround a periphery of the inflow port portion into which the distal end side of the inflator is inserted. The pressing portion is plastically deformable so as to approach a side of the support portion by being crimped, and the distal end side of the inflator inserted between the pressing portion and the support portion and the inflow port portion are sandwiched between the crimped pressing portion and the support portion, and are held by the attachment base.