A rear-seat airbag is configured to expand and deploy from a lower portion of a center console of a vehicle toward a center portion of a row of rear seats. A point of intersection of virtual loci of forward movements of a head, a chest, and knees of a passenger sitting in the center portion of the row of rear seats in response to an impact generated by a collision of the vehicle coincides with a center of gravity of the rear-seat airbag when the rear-seat airbag expands and deploys.