AIRBAG DEVICE

An airbag device includes: an inflator generating gas at a time of a collision of a vehicle; and an airbag to which the gas is supplied, and that inflates and expands from a seat rear side of an upper portion of a vehicle seat toward a seat front side, and slips-through between a ceiling of a vehicle cabin and a head of a passenger seated in the vehicle seat. The airbag has at least one gas supply path that is provided so as to be directed toward the seat front side and whose angle of incidence with respect to the ceiling in a side view seen from a seat transverse direction is set to be an acute angle.