To safely and efficiently manufacture a canopy for a gasoline station without requiring a scaffolding and high-place works by assembling a roof section at the place of ground work and suspending, fixing and completing the roof section. A roof section 2 is assembled around a main frame, and the manufactured roof section 2 is lifted above the main frame. A jig J and the roof section 2 are connected by wires W1 first, and the jig J is hung up by wires W2 by using a jig J crane. Bolts connecting brackets 5 and temporary supports 4 are removed, and the roof section 2 is suspended by the crane. The L-shaped brackets are installed to beams by bolts at the time, rollers engaged with the two side faces of the supports 1a are mounted rotatably on the brackets, and the roof section 2 is guided to the supports and smooth suspension works can be conducted by using the rollers. |