PURPOSE: To simplify execution and repairing work by providing a roof unit with a bearing member main body, a base section bearing the main body, a jack and a bearing member, forming roofing materials in size sufficiently enough to cover a snail area section of setting bed material, and butting adjacent roofing materials and their end faces to arrange.

CONSTITUTION: A setting bed material 2 is so formed in a folded shape that mountain sections 21 and valley sections 22 are arranged in succession, and an overlap section 23 is provided. Then, main bodies 5, fixed members 6, base section 71 and jack 72 are provided to a bearing member 3. Angles and intervals between the main bodies 5 and setting bed material 2 are adjusted. A coupled section 23 of the setting bed material 2 is partially superposed on the adjacent setting bed material 2, and the crest lines of the mountain sections 21 and valley sections 22 are laid on the foundation 8 in the flow direction of the roof. Then, interlocking gutters of scantling roofing materials 4 are interlocked with heads of the fixed members 6, and a roof unit is fixed on a specific position covering the upper surface of the setting bed material 2 by sliding it along the members 6. By the constitution, a large number of roofing materials 4 can be roofed at a time by setting one roof unit 1 on a required position of a skeleton.