US Patent 10343638 Vehicular seat installed with side airbag device

In a vehicular seat installed with a side airbag device, an inside bag completes inflation and deployment earlier than a side air bag body, on the inner side of the side airbag body in the vehicle width direction, and presses an occupant inward in the vehicle width direction. The inside bag inflates and deploys at an upper level than the abdominal region of the occupant. Further, reaction force is applied inward in the vehicle width direction from a reaction force plate supported by an outer side frame, to the inside bag. The reaction force plate extends in a vehicle front-back direction, and extends toward the front of the vehicle beyond a front edge portion of the outer side frame.