To allow hands-free screwing works without holding a screwing tool with hands, when fixing a screwing member with respective to a ceiling surface inside a guide rail for a hanging door.

The tool 20 for fixing the screwing member includes: a holder 21 formed concavely in a top surface and fittably holding the screwing member 11 placed thereon; a screw passage hole 22 formed in a bottom surface of the holder 21; a pair of right and left drooping pieces 23A, 23B formed by being spaced apart from each other at a distance substantially equal to an opening width of the guide rail; and claws 23a, 23b formed on outer surface sides of the drooping pieces 23A, 23B and engaging with opening lip pieces 4b, 4b of the guide rail 4.