Abstract
In IT system development, it is well understood how the quality of the work products ("requirements definition document") of requirements definition phase greatly affect the work of successor phases of the work. Therefore, in systemizing completely new operation and large-scale business development, at times the method of reestimating the development scale after an external design phase may be taken. But, if the process of this requirements definition phase is not carried out precisely, it will result in lowering the quality and credibility of the work products and misleading the process of phase afterwards. Recently, there are some case of problems occurring among middle scale requirements definition phase in IT system development. In order to guarantee the quality of a requirements definition phase for the problem generated in these cases to a key, it considers what should be carried out as PM.
