PURPOSE: To provide a structure wherein basic steel members and splice steel plates are friction-connected strongly to each other with a simple means, and the quality control of the basic steel members and the splice steel plates is made easy.

CONSTITUTION: Basic steel members 2 and splice steel plates 3 are tightly fastened with high strength bolts 1 and are friction-connected with each other. Surface hardness on at least friction-surface side of the splice steel plate 3 is made smaller than that on the basic steel member 2. Surface roughness on at least friction-surface side of the splice steel plate 3 is made smaller than that on the basic steel member 2.