| 摘要 |
PROBLEM TO BE SOLVED: To dispose a pair of headrest supports at proper positions respectively by using one kind of holders.SOLUTION: A first engagement part 11a capable of being engaged to only a first engaged part 21a of a first headrest support HS1 is disposed on one side open end 11, and a second engagement part 12a capable of being engaged to only a second engaged part 22a of a second headrest support HS2 different from the first engaged part 21a is disposed on the other side open end 12. One holder HM1 is fixed to an upper frame 16a in a state that the one side open end 11 faces the first headrest support HS1 side, and the other holder HM2 is fixed to the upper frame 16a in a state that the other open end 12 faces the second headrest support HS2 side. |
