PURPOSE: To easily secure a switch box without exfoliating a surface material by providing a movable piece pressed and brought into contact with the rear face of a wall material using a bolt.

CONSTITUTION: Window holes 8 are opened in side pieces 3, 4, and movable pieces 9 are erected. A folding line (a) is formed at one end of the hole 8, and folding lines (b), (c) are formed at the movable pieces, a threaded hole 9H is opened at a connecting piece 91 of the end, and a bolt 10 inserted into a bolt hole 7H is engaged. A switch box B is pressed into a burying hole 2. When the bolt 10 is clamped, the piece 91 is pulled by the rotation of the bolt 10 from the deep bottom of the box B toward the opening. One end of the piece 9 is sharpened at the bending angle of the folding lines (a), (b) by the movement of the piece 91, and a connecting piece 92 is erected. Further, when the bolt 10 is clamped, a direct piece 92 is pressed and brought into contact with the rear face of a wall material 1. Thus, a switch box can be easily secured without exfoliating the surface material of the wall 1.