SIDE AIRBAG DEVICE

Problem: To provide a side airbag device that can improve restraint performance by efficiently suppressing oscillation of an airbag cushion. Resolution Means: A side airbag device is provided with: a vertically long rear chamber , a front chamber that is inflated and deployed forward and upward from the rear chamber , an inflator contained within a rear part of the rear chamber , and a cloth-like first tether that is provided outside of the rear chamber , has a front end connected to a front edge portion of the rear chamber , and has a rear end connected to the rear part of the rear chamber , and which is tensioned when the rear chamber is inflated and deployed. The rear chamber has a smaller capacity than the front chamber , the first tether is longer in the vertical direction than in the front-back direction, and the front end of the first tether is connected to a range that includes at least a lower end of the front edge portion of the rear chamber