Side airbag apparatus

A side airbag apparatus comprising a bag-shaped airbag main body having an inflation portion and an inflator having a gas outlet that discharges inflation gas for inflating the inflation portion of the airbag main body, wherein

• the airbag main body is formed by a pair of main body fabric portions, wherein the main body fabric portions are overlaid onto each other in a widthwise direction of a vehicle seat,
• peripheries of the main body fabric portions are joined to each other at a peripheral joint portion,
• the airbag main body is deployed forward on a side of an occupant seated in the vehicle seat as the inflation portion is inflated,
• the airbag main body includes
• a lateral partition extending between the main body fabric portions, wherein the lateral partition divides at least a part of the inflation portion into an upper inflation chamber above the lateral partition and a lower inflation chamber below the lateral partition, and an inner tube, which encompasses at least the gas outlet of the inflator, wherein the inner tube extends in the inflation portion and over the upper inflation chamber and the lower inflation chamber, while intersecting with the lateral partition,
• the lateral partition is formed by a pair of structural fabric portions,
• each structural fabric portion has a first peripheral portion and a second peripheral portion,
• the first peripheral portions of the structural fabric portions are each joined to one of the main body fabric portions,
• the second peripheral portions of the structural fabric portions are joined to each other by a joint portion provided along the second peripheral portions,
• the inner tube intersects with the lateral partition at least at a lower end of the inner tube,
• a rear peripheral portion of a part of the inner tube that intersects with the lateral partition is joined to the main body fabric portions by a part of the peripheral joint portion, and
• a front peripheral portion of the part of the inner tube that intersects with the lateral partition is joined to the structural fabric portions by a part of the joint portion.