To provide an excellent steel substrate structure coping with a deformation of a partition wall skeleton of a high-rise building.

Studs 1, which are erected at predetermined intervals between an upper and a lower runner 5 fixed on skeletons such as a ceiling slab and a floor slab or the like, are formed of lips doubling a steel plate by folding cylindrically the tip portion of the U-shaped cross-section back, single-plate flanges having a plurality of grooves, and key hole-shaped webs arranged at predetermined intervals. A substantially U-shaped part of a substantially U-shaped and upward-shaped spacer 2, which is a desired rectangular steel plate, both ends of the short sides have arch shaped cross-section, and cushioning materials are abutted on the outer periphery, is inserted into semi-circular shaped opening 4 of the key hole-shaped stud web from the inside of the stud at a central part of one side of the long sides of the spacer 2. And, the substantially U-shaped part is moved downward along a guide groove provided in a lower portion of the semi-circular shaped opening of the stud web. Consequently, the substantially U-shaped part is held and integrally connected to the stud.