PURPOSE: To efficiently secure an absorption function of energy and contrive to decrease a weight and manufacturing costs by a method wherein a housing part is formed in a cushion support body, and also an absorption member made of at least a half-rigid foaming material is arranged inside the housing part.

CONSTITUTION: A cushion support body 2 formed as a shell is arranged in a backrest 1 of an automobile, and a lower end edge of a side wall 3 projecting frontwardly is coupled to a link metal fitting. At this time, a pocket 5 is formed on a front face of the cushion support body 2. An absorption member 8 is arranged in a part formed integrally with a center part 6 of the cushion support body 2 in the pocket 5. On the other hand, a projection part 9 projecting rearwardly is formed at an end edge on both sides of the absorption member 8, and this is adapted to an expansion part 7 projecting rearwardly of the center part 6. Furthermore, a downward projecting part of the pocket 5 and the absorption member 8 is coated with a cushion 12 mounted on the cushion support body 2. Furthermore, the cushion 12 is coated with a cover 13.