SIDE AIRBAG DEVICE AND METHOD FOR MANUFACTURING THE SAME

A side airbag device stowed in a side part of a vehicle seat and includes: an airbag for restraining an occupant by expanding and deploying; and an inflator provided in a side wall part of a seat frame in the vehicle width direction extending in the vehicle traveling direction when a horizontal cross section of the vehicle seat is viewed from above, and that supplies expansion gas to the airbag. The airbag includes a main chamber that expands and deploys towards the front and a pre-push chamber that expands and deploys before the main chamber to the inside of the main chamber in the vehicle width direction. Furthermore, the pre-push chamber has a structure with an extension portion extending from the inflator towards the rear of the vehicle seat.