PURPOSE: To thatch a roof of a large-sized building with a long stretching roofing material, such as a folded roof panel, easily and with lesser human labor.

CONSTITUTION: Columns 1 in pairs about the direction intersecting the flow directopn of long stretching roofing materials made through a molding process are installed upright, and a wire 2 is stretched over between the columns 1. A hoist 3 is hitched at this wire 2 through a pulley 4, and each roofing material 5 is moved to the place of thatching upon being lifted by the hoist 3. The hoist 3 us turned to put down the rooting material 5 onto a beam, and then the material 5 is secured to the beam.