Vehicle side airbag device and manufacturing method of a side airbag

A manufacturing method of a side airbag, the side airbag including:

• a side airbag main body that is formed of one or more base cloths and that inflates and deploys at a side of an occupant seated in a vehicle seat, and
• an upper-lower partitioning tether that partitions the side airbag main body up and down, that includes a sloped portion with an upper edge sloping toward a seat lower side on progression toward a seat rear side at the seat rear side of the side airbag main body, and in which a lowermost portion of the sloped portion is formed positioned further toward a seat upper side than a stitchable lower limit height, the manufacturing method comprising:
• an upper edge stitching process of stitching the upper edge of the upper-lower partitioning tether to an inner face of the side airbag main body;
• a lower edge stitching process of folding the side airbag main body with the stitched upper edge in two, so as to be superimposed in a seat width direction, folding back a seat lower side of the side airbag main body further to the seat upper side than the lower limit height, and stitching together lower edges of the upper-lower partitioning tether;
• and
• a peripheral edge stitching process of stitching together superimposed peripheral edges of the side airbag main body.