PURPOSE: To provide the structure of mounting electric apparatus to the mouth of a wall panel which is easy in work execution and does not cause gap between the electric apparatus and the recessed section on the surface of the wall panel.

CONSTITUTION: A spot facing part 60 is provided at the periphery on the surface side of the wiring cable drawing-out opening 11 of a wall face panel 10. On the other hand, the tubular joint 21 of a bush 20 which has a flange 22 at the rear, from the rear side of the wall face panel 10, and the tubular connection 31 of a seating member 30 which has a seating part 23 capable of being fit in the spot facing part 60 at the top, from the surface side of the wall panel 10, are inserted into the opening 11. By coupling those tubular connections 21 and 31 with each other, it is put in such condition that the wall face panel 10 is caught by the bush 22 and the seating part 32, whereby an electric apparatus is attached to the seating part 32.