Patent attributes
An airbag includes: a bag main body: and regulating units configured to regulate an expansion completed shape of the bag main body. The bag main body has an expansion completed shape as a substantially square cylindrical shape, where a hollow portion which penetrates substantially along a left-right direction is provided and a circumference of the hollow portion is surrounded by an upper expansion portion and a lower expansion portion and a front expansion portion and a rear expansion portion. The regulating units are arranged at a plurality of horizontally symmetrical locations centered on a center of the bag main body on the left-right directional side and each of the regulating units is configured to straddle the hollow portion when viewed from a lateral side in the left-right direction and at least an upper edge side and a lower edge side are connected to the bag main body side.
