PURPOSE: To develop the software of high quality with high efficiency by analyzing the quality of the result obtained by a state transition chart quality measuring means and displaying the result of analysis.

CONSTITUTION: A state transition chart editing device 1 uses a state transition chart 5 as an input and edits automatically the chart 5 into a form that can undergo the quantitative evaluation through a pattern state transition chart quality evaluating device 2. The device 2 also measures the chart 5 edited by the device 1 in terms of the quality. Then a quality measuring result analyzing device 3 performs the analysis of quality based on the quality measuring result of the device 2. Furthermore a quality measuring/analyzing result display device 4 displays the result of evaluation to the users based on the analyzing result of the device 3. Thus the software of high quality is developed with high efficiency.