PURPOSE: To make safe a high place work by mounting struts to ceiling beams so as to project the front ends of the struts to a rooftop so that they are capable of loading and unloading, and laying a life line between projections of the struts to the rooftop to carry out the work.

CONSTITUTION: First of all, housing units 11 are manufactured at a factory, and mounting bands 4 are provided to ceiling beams 13 of the units 11. After that, the units 11 are transported to a construction site to fabricate. Then, each of struts 3 is inserted between the band 4 and the beam 13 from the root thereof, and it is fixed with a bolt. Then, a master rope 31 is hung on hooks provided to the front ends of two struts 3 projected to the rooftop. A life line is hung on the master rope 31, installation of roof members 2, and work between the units 11 are carried out, the struts 3 are removed from the beams 13 after the execution, and places for the struts 3 are finished. Accordingly, a high place work can be safely carried out.