The reform of the central government ministries and agencies was intended to create a new administrative system for the 21st century. A key issue in those reforms was to strengthen the functioning of the Cabinet. In order to achieve national governance directed by the Prime Minister, the reform aimed to provide greater assistance to the Prime Minister.

The Cabinet Office was established in January 2001 after five years of discussion and preparation. The Cabinet Office is not merely the organization which integrates Prime Minister's Office, the Economic Planning Agency and the Okinawa Development Agency, combined with part of the Management and Coordination Agency, the Science and Technology Agency and the National Land Agency, but a new organization with powerful functions of the drafting of plans and the comprehensive coordination.