PURPOSE: To form steel pipe for through column with a column beam junction part as a whole by inserting and shrinkage-fitting a short thick-wall steel pipe in a steel pipe for column and forming a column beam junction part of double pipe structure in order to reinforce a junction part between the steel pipe for through column and the beam.

CONSTITUTION: After inserting a steel pipe 1 for through column and a short and a little large-diameter steel pipe 2 whose cross section is similar to it from one end surface of the steel pipe 1 for through column and heating them roughly uniformly to a prescribed temperature, it is confirmed that the thick-wall steel pipe 2 exists at the column beam junction part position of the steel pipe 1 for through cold. Before heating temperature goes down, they are compressed from the outside, hot-drawn, and fitted to each other to form and cool a double pipe structure, and form a column beam junction part by shrinkage-fitting of double pipe reinforcing between steel pipes each other.