To easily produce an insertion fixture to be inserted into a through hole of a ceramic hollow rod shaped building material.

The insertion fixture 20 comprises an elongated main part 30 and a pair of short end parts 40 which are respectively fixed to both ends of the main part 30. The main part 30 has an L shaped section in the direction orthogonal to the longitudinal direction of the insertion fixture 20. The end parts 40, 40 and both the ends of the main part 30 are overlapped and fixed to each other through spot welding in a way that a cross corner part of a first piece 41 and a second piece 42 of the end part 40 abuts on an intersecting salient corner portion of a first piece 31 and a second piece 32 of the main part 30. A whole length of the insertion fixture 20 is adjusted by adjusting the overlapping part t of the end part 40 and the main part 30, so that the insertion fixture with a prescribed length is easily produced.