PURPOSE: To make the structure of a multi-purpose high-rise building reasonably accomodative to multiple purpose, and to make transmission of stress in the vertical direction smooth by a method wherein the upper and the lower stories are constructed in different structures, each accomodative to its own purpose, and a conversion story is provided on the boundary between the upper and the lower stories.

CONSTITUTION: In a high-rise building 1 whose upper stories are used as dwelling stories 2 and the lower stories are used as office stories 3, a conversion story 6 is arranged to one or a few stories forming the boundary between the dwelling stories 2 and the office stories 3. The dwelling stories 2 are suitably constructed in rigid frame structure. The office stories 3 are suitably constructed in a structure in which an external tube in a double-tube structure and an internal frame are connected with flat slabs. The conversion story 6 is constructed of beams, slabs, diagonal members and others so that stress from the upper stories can be transmitted smoothly to the lower stories.