To surely hold a fitting clock part even when using a material having a large size tolerance at the completion time for an armoring frame.

The clock part B is disposed on the front side of a hole part 1 penetrating the armoring frame A, and a mounting plate C is disposed on the back side. The clock part B has a shell part 3 abutting on the periphery of the hole part on the front face of the armoring frame, and the shell part 3 is provided detachably with a back case 4. A collar part 10a jointed to the periphery of the hole part on the back face of the armoring frame is formed on the mounting plate C, and an attaching screw 11 screwed with the back case 4 through the hole part 1, for pressing the shell part 3 to the periphery of the hole part on the front face of the armoring frame through the back case 4 to fix the clock part B to the armoring frame A is provided. At least the back case 4, the mounting plate C and the attaching screw 11 are made of a metal.