AIR-BAG APPARATUS

An air-bag apparatus includes: a bag body that is provided on a vehicle seat and that is inflated and expanded at a time of an impact input and prevents at least an upper part of a body of an occupant seated on the vehicle seat from being separated from a seat back of the vehicle seat; an inflator that supplies a gas to the bag body at a time of an impact input; a body size detection part that detects a body size of the occupant seated on the vehicle seat; and an expansion degree adjustment part that adjusts a degree of an inflation expansion of the bag body in accordance with the body size of the occupant detected by the body size detection part.