To realize a roofing material layout system, in which various information required for reproofing at a site is indicated rapidly even when a roof drawing is not left by obtaining the coordinate information of the whole surface of a roof only by the take size of the eaves edge side and which contributes to the satisfaction of a customer and an improvement in sale efficiency.

The three-dimensional coordinate values of the contour points of the whole roof are operated arithmetically from the three-dimensional coordinate values of contour points in the eaves-edge contour of the roof and the grade values of each roof surface while a required roofing material is laid out to the required roof surfaces by arithmetically operating the shapes of each roof surface from the three-dimensional coordinate values.