PURPOSE: To easily and surely embody securing a screwing amount necessary for vertical suspension while shortening a time for mounting/removing a suspending metal fixture in the case of the vertical suspension, while suspension supporting can be safely and surely performed even in the case of a shallow screwing amount of the suspending metal fixture at the time of lateral suspension.

CONSTITUTION: A metal fixture inserting hole 1a is formed in a fixed member 1. In this inserting hole 1a, its internal peripheral surface is threaded to be engraved with an internal thread 3 of length corresponding to an internal diameter of this inserting hole 1a relating to the internal peripheral surface in the internal part from the halfway in the inserting hole 1a. In the internal thread 3, its bottom part diameter is formed so as to be almost equal to the diameter in an internal peripheral surface in the point end side from the halfway containing an opening part 2 of the metal fixture inserting hole 1a.