本研究針對2007年至2011年的非金融產業之上市櫃公司，分析股權結構、公司特性是否為公司內部監察人設置比率及是否設置外部監察人之影響因素，並進一步探討公司監察人內部化比率與外部監察人之存在對公司之經營績效、盈餘品質及財務報導強制重編次數的影響。 實證結果顯示，若公司型態為電子公司、家族企業或集團企業、公司之企業規模、內部人持股比率越大，則該公司內部監察人席次比率越高，且不傾向設置外部監察人。而就公司監察人內部化對公司之經營績效及財務報導品質的影響，實證結果顯示，監察人內部化比率越高之公司，其公司經營績效越差，且被要求強制重編財務報表的次數也較多。但只要存在一位外部監察人，即有助於改善公司之經營績效並降低公司被要求強制重編財務報表的可能性。惟本研究並未發現監察人內部化比率或外部監察人之存在與公司盈餘品質間存在顯著關係。 整體而言，本研究之實證結果顯示公司監察人內部化將使法制上監察人制度所應有之公司治理機能無法發揮，無法提升公司經營績效及財務報導品質。故為讓公司監察人能發揮其制度上應有之功能，公司之監察人，宜由外部人擔任。 / Based on a sample of listed non-financial companies over the period of 2007 to 2011 in Taiwan, this study first investigates the impact of ownership structure and firm characteristics on the internalization of supervisors. A step further, this study examines the effect of internalization of supervisors on firm performance, earnings quality and the frequency of restatement of financial reports. The empirical evidence shows that firms operate in electronic industries, or belong to business groups or owned by families, or with greater shares held by insiders or with larger firm size, are significantly and positively (negatively) associated with the internalization of supervisors (the presence of outside supervisors). The study also finds that firms with higher degree of internalization of supervisors are associated with poorer performance and higher frequency of restating their financial reports. On contrary, we find that firms with at least one outside supervisor are associated with better performance and lower frequency of restating financial reports. However, this study fails to report any association between the internalization of supervisors (or the presence of outside supervisors) and earnings quality measured by accruals. Based on the findings, this study therefore suggests that firms should appoint outsiders to be supervisors in order to better serve the function of the institution of supervisors.