A behavior control airbag apparatus including: a floating cushion disposed in a seating part of a seat, and configured to push up a passenger on the seating part while deployed by gas injected by an inflator; and a behavior cushion disposed eccentrically on an outboard side of the floating cushion, and configured to push up the outboard side of the passenger according to the injection of the gas, such that the passenger is inclined to an inboard side.