The new public mangement (NPM) has now been in fashion in many developed countries. The change from cash accounting to accrual accounting is considered an important tool in NPM. The New Zealand Government and the executive agencies in the UK transfered to accrual based budgeting and accounting, while the member countries of EU and the US Government control the expenditures in cash based. This paper aims to explain why the different approaches are adopted in public sector reforms in terms of comparative institutional analysis. Firstly, a multiprincipal and agent model, which expands the contingency model in
accounting reforms into the arena of management reforms, is presented. By using the model, the reforms in the Japanese local governments are
examined and their possible reforming scenarios are indicated; the reforms have the possibility of improving accountability and efficiency when NPM would be integrated with Planning, Programming and Budgeting System.