To provide a device for displaying the state of a roof tiled by using different types of tiles having different surface configurations.

This device displays a state obtained when at least a part of the roof is tiled by a plurality types of tiles having the surface configurations different from each other. The device comprises a roof shape acquisition means for acquiring the shape of the roof at a portion tiled by the plurality types of tiles, a tile shape acquisition means for acquiring the shape of the tiles, a tile position calculation means for calculating the positions of the tiles at the portion by using the shape of the portion acquired by the roof shape acquisition means and the shape of the tiles acquired by the tile shape acquisition means, a tile position and type involving means for involving either type of the plurality of types of the tiles according to a specified relation to the positions of the tiles calculated by the tile position calculation means, and a display means for displaying so that the types of the tiles involved to the positions of the tiles by the tile position and type involving means can be identified.