PURPOSE: To facilitate execution of works by a method, wherein a tenon protective edge and a tenon, an extending way, and a pipeline hole or the like are formed onto a main body, hollow wall components are formed in the vertical and lateral directions, the wall components are combined and wirings and pipings are incorporated.

CONSTITUTION: Tenon edges 11 are formed at one edge of a main body 1, and a recessed groove 110 is formed between the two tenon edges 11 and the upright surfaces of the tenon protective edges 11 and the connecting surface of the recessed groove 110 are formed in the protective contact surfaces 111 of inclined planes. A pipeline hole 14, penetrated through the main body 1 in the lateral direction, is formed into the recessed groove 110, and an extending way 13 penetrated at the center of the main body 1 in the vertical direction is formed and crosses at an angle of 90° with the pipeline hole 14. Two tenons 12 are formed at the other edge of the main body l, a recessed groove 120 is formed between the two tenons 12 and a unit is formed, and a plurality of the units are combined and the protective contact surfaces 111 and contact surfaces 121 are stuck fast. Accordingly, wirings and pipings can be adjusted arbitrarily in both the lateral and vertical directions.