An airbag of an airbag device for the driver's seat of the invention is stored in a way that a carbody-side wall part and a driver-side wall part are overlapped and spread flat, and the airbag is folded in three steps so that widths between opposing outer edge portions with a gas opening as the center are reduced. In the first step of the folding, the carbody-side wall part and the driver-side wall part are overlapped and spread flat, and then right and left edge portions are folded toward the carbody-side wall so that wound regions are provided. In the second step of the folding, areas by front and rear edge portions are folded toward the driver-side wall, so that two regions that have been folded each cover approximately half the gas opening. In the third step, areas by the right and left edge portions that have been folded in the second step are folded in such a manner as to be bent upward. The airbag device for the driver's seat of the invention can secure thickness of the neighborhood of a center of the airbag in the initial stage of expansion of the airbag.