PURPOSE: To early execute wiring and adjusting of a distribution board by splitting the case of the board into a distribution board for mounting a breaker and a distribution board cover for covering the body, individually forming them, and forming the size of the cover larger than that of the body.

CONSTITUTION: The case of a distribution board A is split into a distribution board body 1 and a distribution board cover 2, and individually mounted. Thus, the body 1 can be previously mounted before the wall cloth is adhered, and wirings and regulation can be early executed. This can be performed after the body 1 and the cover 2 are separated and individually mounted. Since the body 2 is formed larger than the body 2, the way of forming a boundary between the body 1 and the cloth is concealed by the cover 2, thereby improving the external appearance.