PURPOSE: To make unnecessary welding work in a site and to have joining construction with high reliability by making it possible to join a column to a beam by built-up work only such as fitting, etc.

CONSTITUTION: Joining construction 10 is constituted of a pair of up and down first joining cylindrical body 13A and second joining cylindrical body 13B lying between a steel pipe 11 and beam members 12 and an end plate 15 lying between a plurality of couplers 14 and the beam members 12. After a lower side steel column 11B is erected with the joining cylindrical body 13B as the upper end, the beam members are lifted to insert the lower end of the end plate into a second joining groove 132B, and after that, the lower end of the first joining cylindrical body 13A is fitted to the upper end of the second joining cylindrical body 13B and, at the same time, the upper end of the end plate 15 is fitted into a joining groove 132A thereof to join the beam members 12 to the steel pipe column 11. In addition, the couplers 14 are fitted into coupling holes 133A and 133B, and the joining of the beam members 12 to the steel pipe column 11 is completed.