PURPOSE: To improve workability by laminating an inner joining member inside a steel pipe concrete column and an outer joining member outside the column, and attaching thereto a split tee with a beam flange welded.

CONSTITUTION: An outer joining member 3 is temporarily installed outside a part of a circular steel pipe column 1 where the flange of the beam 2 is to be welded, and a split tee having the welded flange of the beam 2 is overlapped on the outer joining member 3. In addition, an inner joining member 5 is overlapped from the inside of the circular steel pipe column 1, and the outer joining member 3 is sandwichedly fastened by a high-strength bolt 6 to join the circular steel pipe column 1 with the beam 2. Thus, since welding for the joined part is minimized, and only drilling is utilized for manufacture, workability can be improved.