Abstract: During a software designing operation, a designer accesses a level prescribing unit through an interaction managing control unit. The level prescribing unit provides the guidance to specification information and design parts, etc. at a desired design level. If the designer selects and inputs specification information or design parts, the design editor corresponding to the design specification information in a design editor unit is activated, so that the designer is guided and aided through a display to produce a desired software. At this time, the information about the state of the editing operation "completed" or "not completed" is stored with the directory. The designed document satisfying a specific condition, for example, a document determined to be "design completed", is stored as a data base by a design data base storing unit.