IN-SEAT AIRBAG DEVICE

An in-seat airbag device, includes: an airbag main body having a front-rear chamber that, due to gas jetted from an inflator, expands past a side of a head of a passenger toward a seat front side and is disposed at the side of the head of the passenger, and a distal end chamber that expands from a seat front side end portion of the front-rear chamber toward a seat width direction inner side and is disposed at a seat front side of a face of the passenger, wherein the airbag main body is accommodated in a state of having an outwardly-wound portion that is wound outwardly in a form of a roll whose axial direction is a seat vertical direction, after a distal end portion of the distal end chamber is folded-over toward a side opposite a passenger side.