PURPOSE: To make it possible to stably fix a hook for a ceiling rail to this ceiling rail and to easily and rapidly carry out an operation to mount and remove this hook.

CONSTITUTION: The top end of a shaft piece 29 is provided with an engaging piece 31 having an approximately rectangular shape and the bottom end of this shaft piece 29 is extended and provided with a hook part 30. Further, the shaft piece 29 is provided with a threaded part 32 near its bottom end and a threaded part 32 disposed at a cap 33 of a U shape in section is screwed to this threaded part 32. Further, a contact piece 34 is loosely fitted to the shaft piece 29 at the rear surface of the engaging piece 31 and a coil spring 35 is interposed between the contact piece 34 and a cap 33 to energize the contact piece 34 upward.