To readily and safely construct a light-weight attic heat reflecting and heat insulating material which prevents condensation, while eliminating risks in constructing heavy compound materials on conventional roofs to reflect and insulate heat thereupon, and by reducing long construction time.

A heat-reflecting and insulating board with air permeable cuts (9) with a double-side aluminum-deposited corrugated board (1) or one-side aluminum-deposited corrugated board (8) is inserted between main houses (2), (2). The inner folds (7) are bent inward and pushed up to a roof rafter (3) to be attached to the main house (2) and the rafter (3) for construction.