Completely folded body of airbag

An airbag assembly comprising:

• a folded body of an airbag having an inflow opening through which an inflation gas is allowed to flow;
• and
• a retainer which is assembled to the folded body in order to attach the folded body to a storage portion, the retainer including:
• an annular bottom wall portion having a communication opening, which is open in correspondence to the inflow opening, in a center;
• a plurality of fixing units which protrude downward from the annular bottom wall portion, which is centered on the communication opening, around the communication opening, and are fixed to the storage portion;
• a reinforcing rib which is arranged to stand from an outer circumferential edge of the annular bottom wall portion;
• and
• an airbag cover that includes a side wall portion that surrounds the folded body of the airbag, the side wall portion of the airbag cover includes an upper end and a lower end located closer to the annular bottom wall portion of the retainer than the upper end, wherein
• the annular bottom wall portion of the retainer is disposed in a circumferential edge of the inflow opening on an inner circumferential surface side of the airbag, and is arranged in the airbag in a state where one or more of the plurality of fixing units protrudes outside the airbag;
• the folded body of the airbag is configured in such a folded shape that the airbag is folded to be gathered to an upper side of the retainer in a state where the circumferential edge of the inflow opening is disposed on a lower surface of the annular bottom wall portion of the retainer;
• the folded body is attached to the storage portion by fixing the one or more fixing units, protruding outside of the airbag, with an attachment seat of the storage portion so as to attach the circumferential edge of the inflow opening to the attachment seat of the storage portion;
• the folded body is arranged, on a bottom surface side, with a bottom wall cover portion which is disposed on the lower surface of the annular bottom wall portion of the retainer and a bottom wall separated portion which extends from the bottom wall cover portion and is disposed around the annular bottom wall portion of the retainer;
• a portion, which is connected from the bottom wall cover portion, of the bottom wall separated portion includes a stepped surface having a vertical surface bent upward from the bottom wall cover portion, and a lower-most horizontal surface with respect to the lower end of the airbag cover, the lower-most horizontal surface is disposed above the bottom wall cover portion from an upper end of the vertical surface, disposed above the lower end of the airbag cover, extends toward an outer circumferential edge of the bottom wall separated portion, and is separated from a portion around the attachment seat of the storage portion in a state where the folded body is fixed to the storage portion so as to form a recess portion recessed from an outer circumferential surface of the folded body;
• and
• the lower-most horizontal surface of the stepped surface of the folded body of the airbag is separated from a base plate portion of the storage portion so as to form a gap, the base plate portion including the attachment seat, wherein
• the vertical surface of the stepped surface is bent upward from the bottom wall cover portion in a state where the vertical surface is in direct contact with an outer circumferential surface of the reinforcing rib of the retainer.