Front airbag with hollow portion

An airbag, which is folded and accommodated in front of an occupant seated on a seat in a vehicle and is configured to allow expansion gas to flow inside and be developed and expanded so as to protrude from an accommodation part toward a rear side to be able to protect the occupant, the airbag comprising:

• a bag main body configured to be expanded by inflowing expansion gas into the inside;
• and
• a plurality of regulating units configured to regulate an expansion completed shape of the bag main body, wherein:
• 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 arranged substantially along a front-rear direction on both upper and lower sides and a front expansion portion and a rear expansion portion arranged substantially along an up-down direction on both front and rear sides, and the rear expansion portion arranged on an occupant side when expansion is completed is defined as an occupant protection portion capable of protecting the occupant and a mounting portion to be attached to an accommodation part side is arranged on a front end side when the expansion is completed;
• the regulating units are arranged at a plurality of horizontally symmetrical locations centered on a center of the bag main body on a 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 a bag main body side;
• and
• the upper expansion portion is configured such that a part on the front end side communicating with the mounting portion and the front expansion portion has a narrow width in the left-right direction and a part on the rear end side communicating with the occupant protection portion has a wide width in the left-right direction.