Side airbag device

A side airbag device disposed between a vehicle body and a seat, the side airbag device comprising:

• an airbag;
• an inflator configured to supply the airbag with gas;
• a base member configured to accommodate the airbag and the inflator, and to be fixed to the vehicle body;
• and
• an outer covering member configured to cover at least a front side of the base member to form a front-facing interior surface,
• wherein the base member comprises:
• an inner portion located laterally farther inward within the vehicle body relative to the airbag;
• an outer portion located laterally farther outward within the vehicle body relative to the airbag;
• a rear portion located farther rearward relative to the airbag with respect to a front-rear direction of the seat, the rear portion connecting the inner portion and the outer portion;
• and a bridging portion made of a metal rod, and located apart from and farther frontward relative to the rear portion, the bridging portion connecting the inner portion and the outer portion.