PURPOSE: To make a job at a construction site simplifiable as well as to enable it to progress smoothly and promptly.

CONSTITUTION: Plural pieces of outer wall panels 13 to be set up by slinging up in a prefabricated building 11 with a crane 16 are presorted at each side of north, south, east and west or bearings of this prefabricated building 11. In succession, at the time of execution of works, these outer wall panels 13 of assortment corresponding at each bearing are set up in the order of north, south, east and west in advance. Therefore, lifting setup work of the outer wall panels 13 for each outer side of the building 11 is unnecessary to divide into plural times, and the crane 16 is able to reduce its travel within the job site to the irreducible minimum of necessity.