To allow even a person without special knowledge or technique to easily design an object to be constructed such as the interior decoration and external appearance of a building by calling a unified impression.

A main map is set to every object to be constructed constituting the interior decoration and external appearance of the building to set plural auxiliary maps corresponding to this main map. Two-dimensional coordinate consisting of a taste element axis and a use element axis is constituted for each of these maps to arrange a constructing object such as the photograph of a living room given interior decoration in the main map and a constituting element such as illuminator, an interior material in the auxiliary maps by relating with each element axis. Each map is stored in a temporarily storing part 11c. The main map is read first and displayed on a picture display device 14 to select a desired constructing object to store in a temporarily storing part. In addition the auxiliary map is successively displayed to select and store the constituting element. The constituting element are composited with the stored object to be constructed for designing.