PURPOSE: To firmly install a metal hanger on the bottom face of a floor slab to hang a ceiling, facility pipings and others.

CONSTITUTION: A metal hanger main body 12 has a nut 13 on a bottom part 12a and an engagement part 12g projecting to the left side. This engagement part 12g is engaged with a groove part 1c of an inclined web face 1b of a deck plate 1. An engagement member 14 with an inclined face part 14d is installed on the metal hanger main body 12 free to move sideways. When a hanging bolt screwed in the nut 13 is turned, the hanging bolt rises, makes contact with the inclined face part 14d and pushes the engagement member 14 out to the right, and its top end part 14a locked with the groove part 1c on the other side of the deck plate 1. When the hanging bolt 18 is further turned and raised, it strongly hits the bottom face of the deck plate 1, the engagement part 12g on the left the metal hanger main body 12 and the top end part 14a on the right of the engagement member 14 are firmly engaged with the groove part 1c, and a metal hanger 11 is firmly fixed on the bottom face of a floor slab 10.