Abstract: A building construction of longitudinal and cross hollow components includes building unit bodies each of which consists of joggles, scarfs, extension paths and wiring holes, such that, after a plurality of such unit bodies are formed into a wall, it forms transverse penetrating wiring paths with a gradient and longitudinal paths to assure convenient wiring construction. It also has the advantages of fire-proofing, heat discharging, and prolongation of rescue time when the building is on fire.