Seat back

A seat back comprising:

• a frame that forms a framework;
• and
• a cushion member that is attached to the frame and elastically supports a seater, wherein the cushion member comprises
• a main member located at a center portion in a seat width direction, the main member comprises a main pad, a main cover enclosing the main pad, and a main support member attached to the frame side of the main pad for supporting the main pad, and
• a pair of side members located on both sides of the main member, each of the pair of side members comprises a side pad, a side cover enclosing the side pad, and a side support member attached to a frame side of the side pad and configured to support the side pad,
• wherein at least one of the side members includes an airbag device,
• wherein a folded portion having a substantially U-shaped cross section opening rearwardly is formed at the side support member of the side member in which the airbag device is located, wherein each of the pair of side members is formed by placing the side pad on a front side of the side support member, covering with each of the pair of side members with the side cover, and inserting a resin plate attached to the side cover into a folded portion of the side support member, wherein the side cover further comprises a main portion enclosing the side pad and a secondary portion enclosing a side of the folded portion, wherein the main portion and the secondary portion are sewn at a first sewing portion extending along front end of the folded portion, wherein one end of a first stay cloth arranged at a front of the airbag device is fixed to the frame, wherein one end portion of a second stay cloth arranged at a rear of the airbag device is fixed to the frame, wherein the other end of the first stay cloth and the other end portion of the second stay cloth are integrated with the main portion and the secondary portion by sewing at the first sewing portion, wherein the second stay cloth is arranged to abut on a corner portion of the folded portion, and wherein the first sewing portion is torn by deployment pressure from the airbag device.