When an occupant has moved from a normal seating position, a case can occur where a hood-type airbag cannot be expanded and deployed since the airbag is stopped in the process of expansion and deployment due to contact with the head of the occupant. An airbag device is provided having an airbag, and an inflator for supplying gas to the airbag. In an expanded and deployed state where expansion and deployment of the airbag has been finished, the airbag includes a head protection chamber for blanketing an occupant from a vertex part of the head to a temporal part of the head, and a pair of lateral part protection chambers that are arranged on both of the left/right sides of the head protection chamber and that blanket lateral sides of the occupant.