AIR BAG APPARATUS

An air bag apparatus includes: an inflator that generates a gas when an impact is input; and a bag body that is supplied with the gas from the inflator and that is inflated and expanded from a seatback of a vehicle seat. The bag body includes: a trunk support part that is expanded to an opposite side of the seatback so as to support a trunk of an occupant who is seated on the vehicle seat; and a pair of head support parts each of which is expanded to each of both sides in a width direction of the vehicle seat so as to support a head part of the occupant and that is connected to the trunk support part. An escape part that penetrates in a vertical direction between the pair of head support parts and that avoids the head part of the occupant in an expansion state is formed on the bag body.