PURPOSE: To improve usability and secure external appearance by providing a steel profile for receiving the attaching flanges in a fixing support body to a ceiling or a wall and connecting lining sheets or the like and enclosing the connected parts by a closing member of the support body.

CONSTITUTION: Two profiles 2 are provided in the longitudinal direction of a support body 1 and respective profiles 2 are parallelly and obliquely extended in the vertical direction. The external edge of the profile 2 is lined up with one edge 4 of the side face of the support body 1. Next, the other edge is made longer than the first edge 4 while forming a ridge 5. A closing member 3 for the support body 1 made of a U-shaped steel profile is brought into contact with the edge 4 of the support body 1. A ridge 6 cooperating with the ridge 5 is provided at the external free end of one wing. After the flange of the edge corresponding to the connecting sheets is inserted in the profiles 2, the flange of the other edge is inserted in the peripheral support body 1 to lay the sheet. Subsequently, the closing member 3 of the support body 1 is fitted to be fastened onto the support body 1 by bolts and nuts. Finally, the other edges of the sheet is fastened.