An information sharing area, employed by all conferees for sharing information (object) or personal knowledge transmitted via information processors from conferees, and an editing display area, employed for editing a structure of the information (object) or shared knowledge, can be definitely distinguished from each other and displayed in a large display device commonly visible from all, conferees. When the areas are displayed in the large display device and one of the objects displayed in the information sharing area is designated, the designated object is displayed at a desired location in the editing display area and can be edited through cooperative works by all conferees centering around a conference chairman.