Abstract: An airbag apparatus includes a controller, a prediction unit, and a sampling-period control unit. The controller conducts sampling of acceleration values output from a plurality of acceleration sensors disposed on a vehicle and controls inflation of an airbag based on the sampled acceleration values. The prediction unit predicts a collision direction in which collision with another vehicle would occur. When the prediction unit predicts the collision direction, the sampling-period control unit shortens a sampling period for the acceleration sensor disposed in the predicted collision direction in comparison with sampling period for the other acceleration sensors. After the sampling-period control unit shortens the sampling period, the controller determines whether or not to inflate the airbag, based on the sampled acceleration values output from the acceleration sensor disposed in the predicted collision direction.