To eliminate the welding fixture, etc., of a diaphragm to a steel framed column in a joint section between an enclosed section column and a beam, facilitate the reduction of the process of work in a steel framed processing plant and the quality control, obtain the frame construction of rigid joint without applying thickness increment processing or reinforcing plate mounting to the steel framed column and requiring to have bolt holes in the steel framed column and to enable the reduction of the number of bolts because of using high-strength bolts with a large diameter.

A horizontal member 3a having nuts 7 screwing joint bolts 5 from beam sides and a nut hardware 10 is fixed around a steel framed column 1 in a band-shape to form a horizontal frame body 3, and sleeve hardwares 4 are so provided to flanges 2a of the steel framed beams 2 that the end faces of them on the column side can be brought into contact with the surfaces on the beam sides of the horizontal frame body 3. The front ends of the joint bolts 5 inserted into the sleeve hardwares 4 are screwed in the nuts 7, etc., to clamp, and the frame construction of rigid joint is constituted.