This paper is a case study research of accounting information system structured by ERP and common journalizing between financial accounting and management accounting. It enhanced consistency between financial accounting and management accounting. 　This case study is an action research, for the author took part in the introduction project of this system as project manager at consumer finance company. The major issues discussed in this paper can be summarized as follows : 1. Introducing management accounting method into financial reporting for investor relations 2. Better internal control for financial reporting by utilizing information technology 3. Using ERP effectively