PURPOSE: To simplify the leveling of a water-proof pan.

CONSTITUTION: The wall panel mounting section 42 of a water-proof pan 38 is fitted into a frame body 36 from the upper section. On the adjuster bolt 48 of the horizontal upper section angle 46 of the frame body 36, a reinforcing wooden piece 44 on the lower surface of the wall panel mounting section 42 of the water-proof pan 38 is mounted, and the level is regulated, and the leveling of the water-proof pan 38 is performed. After that, a tex-screw 50 is driven into, and the frame body 36 and the water-proof pan 38 are integrated with each other. Accordingly, if the slab in site is horizontally set, the leveling of the water-proof pan 38 can be performed by simply delivering the integrated object of the water-proof pan 38 and the frame body 36 and then installing the object in place.