PURPOSE: To offer an energy saving method applicable to a high-rise building consisting of lower sections of steel pipe concrete column construction and upper sections of half-precast reinforced concrete column construction in the high-rise building having 8 to 15 floors.

CONSTITUTION: Lower sections of a structure are constructed of a steel pipe concrete column, and then, a plurality of connection reinforcing bars 3 inserting parts necessary for longitudinal anchorage of them into the steel pipe column and projecting remaining parts having proper lengths to the outside thereof are arranged to the inside of the steel pipe in the highest part of the steel pipe concrete column construction. After that, the steel pipe column is filled with concrete 6 to form the steel pipe concrete column 1. Then, the connection reinforcing bars 3...3 projected from the steel pipe concrete column 1 are fitted with a half-precast reinforced concrete column 2, and the steel pipe concrete column 1 is combined with the half-precast reinforced concrete column 2 by placing concrete to the inside of the half-precast reinforced concrete column 2. After that, upper sections are constructed of the half-precast reinforced concrete column, etc.