An airbag device for a driver's seat adapted to be mounted on a boss of a steering wheel disposed at a center of a rim is disclosed. The airbag device includes an inflatable airbag folded in the form of an airbag package. The airbag includes a vehicle-side wall that includes a gas inlet port and is configured to be supported by the rim when deployed, and a driver-side wall. The airbag, before folded into the airbag package, has a flat initial folded form in which the driver-side wall lies over the vehicle-side wall. The initial folded form includes a folded-in portion in which a front edge portion of the vehicle-side wall is folded inwardly and rearwardly beneath a front edge portion of the driver-side wall, and a folded-back portion in which the front edge portion of the driver-side wall which adjoins the folded-in portion is folded towards the inlet port on the vehicle-side wall.