An airbag for a driver seat is provided with: a steering wheel of a vehicle; an inflator stored in the steering wheel; and a cushion stored in the steering wheel along with the inflator that expands and deploys to restrain a passenger. The cushion contains: a steering side panel positioned on a steering wheel side; an occupant side panel positioned on an occupant side; and a side panel connecting an edge of the steering side panel to an edge of the occupant side panel to configure a side portion of the cushion. The occupant side panel has a larger area than the steering side panel, and an upper portion of the expanded and deployed cushion is thicker in the vehicle front-rear direction than a lower portion of the cushion.