In the previous works of corporate governance structure, minority shareholders(MS) who has relatively minor impact on ownership structure have been excluded as a observer in corporate management because most of Korean firms are in a family-controlled shape. But According to the adjusted commercial law in 1998, the right of MS has been strengthened : Since the watching systems of board such as outside directors, full-time auditors, audit committee have been introduced by the law, there come a new turning point for MS. This paper aims to provide practical works on the influence of MS as a restraints in manager¡¯s earnings management. This works covered 2,495 firms registered in Korean Stock Exchange from 2001 to 2005 excluding financial and insurance business. Manager¡¯s earnings management is evaluated from discretionary accruals from Jones model(1991) and the model by Dechow et al.(1995) which modified Jones model. The impact of associated variables on ownership structure including MS and other control variables are computed using multivariate regression. According to the research, managers tend to minimize earnings management or to make downward earnings management as portion of MS increases. This seems to represent that MS affect the manager¡¯s earning management. Also influence of MS with regards to separation of ownership and management shows the possibility of participation of minority shareholder in corporate management because MS in manager-controlled(MC) companies affect manager¡¯s downward earning management. However in owner-controlled(OC) companies, due to the strong governance of majority shareholder, the restraining influence of MS on earning management is relatively not as strong as the former case. Regarding board structure, it is shown that the influence of MS in earning management does not change much depending on whether the minimal required selection of outside directors or audit committee is introduced. But MS affect a lot in the earnings management in the case of companies which have more outsider directors than required. As a result of this work we has shown that minority shareholder plays an important role in ownership structure and practical results with regards to minority shareholder are presented. In the future, the more systematic works should be continued because the impact of minority shareholder in governance structure is expected to continue to increase.