Side airbag apparatus

A side airbag apparatus comprising:

• an airbag formed in a bag-like shape by laying an inner fabric portion and an outer fabric portion on top of each other along a widthwise direction of a vehicle and joining the peripheral portions of the inner and outer fabric portions with each other;
• an inflator that supplies inflation gas into the airbag in response to a side impact applied to the vehicle and inflates and deploys the airbag between an occupant seated on a vehicle seat and a body side portion of the vehicle and toward a front portion of the vehicle;
• and
• a looped pressure reducing portion formed by joining the inner fabric portion and the outer fabric portion together at a position corresponding to an arm of the occupant,
• wherein the airbag has a linear portion that extends substantially perpendicularly to a deploying direction of the airbag and is located at a rear end portion of the airbag, the inflator being arranged in the linear portion of the airbag, the pressure reducing portion limiting a thickness of the airbag in the widthwise direction of the vehicle at the position corresponding to the arm of the occupant, thereby preventing the airbag from pressing the arm inward in the widthwise direction of the vehicle,
• wherein a support joint portion joining the inner fabric portion and the outer fabric portion together is arranged at a position that is located below a lower end of the pressure reducing portion and behind a front end of the pressure reducing portion when the airbag is arranged in such a manner that the linear portion is held in a posture extending vertically, and
• wherein the support joint portion projects toward the pressure reducing portion beyond a line including a lower end of the airbag and a lower end of the inflator, and an end of the support joint portion located close to the pressure reducing portion is located below the lower end of the pressure reducing portion.