The fixture 10 includes a base member 100 having a length capable of straddling a plurality of ribs, a groove portion 101 formed on the base member 100, in which an end of a bar is slidably fitted, and a surface of the base member 100 on the groove portion 101 side. The screw hole 104 formed in the screw hole 104, the screw 701 screwed into the screw hole 104, and the end of the bar fitted in the groove part 101 are brought into pressure contact with the groove part 101 by tightening the screw 701 with respect to the base member 100. The 1st pressing member 400 which fixes the edge part of this to the groove part 101 is provided.固定具１０は、複数の肋骨を跨ぎ得る長さ有するベース部材１００と、ベース部材１００に形成され、バーの端部が摺動可能に嵌められる溝部１０１と、ベース部材１００の溝部１０１側の面に形成されたネジ孔１０４と、ネジ孔１０４に螺合されるネジ７０１と、溝部１０１に嵌められたバーの端部を、ベース部材１００に対するネジ７０１の締め付けにより溝部１０１に圧接させて、バーの端部を溝部１０１に固定する第１の押さえ部材４００と、を備える。
