The aim of this paper is to investigate 1) the difference between property of vertical network organization and one of horizontal network organization in product development, and 2) which property of vertical network organization introduces high performance in product development. After the reviewing about inter-organizational theory in sociology, and accounting which is close to network organization, it becomes clear that 1) formal and detailed management concludes high performance in vertical inter-organization, 2) on the other hand, reliability and/or information sharing, informal relationship are important factors in the horizontal network organization. After discussing in settlement of prior research, five hypotheses are introduced at the moment. Then, four case researches are discussed. Finally, case of artificial satellite development in Kagawa University is studied. The results show the consistency between prior researches and the case.