AIRBAG DEVICE

An airbag device includes an airbag having an exhaust hole and a flap member that can close off the exhaust hole. The flap member includes a flap main body and a coupling member. The leading end of the coupling member is coupled with an opening/closing control device. The flap main body closes off the exhaust hole from an inner peripheral face side of the airbag. A width on the base portion side is set to be greater than a width of the exhaust hole. Whole of the base portion side is joined to the peripheral edge of the exhaust hole in the airbag. The flap main body covers the exhaust hole in a region between straight lines that connect one end each of a joint region on the base portion and a region on the leading end to which the coupling member is caused to be coupled.