本文從經濟分析之觀點，首先介紹著作權法第六十五條就判定「合理使用」之概括規定及其理論背後之經濟觀點，其次，再介紹智慧財產法院 98 年度民著訴字第 8 號民事判決之內容，最後，再就該判決內容採取「阻卻違法說」之經濟分析論點，加以評析，並就該判決未具體詳述之經濟觀點，從「市場失靈模式」、「利益平衡模式」及「效率極大化模式」等允許「合理使用」之三種經濟理論，提供較深入之經濟分析，期能彌補司法實務上判決理由不夠完善之缺憾，並主張我國著作權法第六十五條之規定，應係採「利益平衡模式」之經濟理論。

This article, from the viewpoint of economic analysis, first introduces article 65 of Copyright Law regarding the general provision of fair use doctrine and its economic viewpoints behind this theory. Second, it summarizes the content of 98 Nian-Du Ming-Zhu Shang-Z No. 5 judgment. Finally, it comments on the economic viewpoint in this judgment regarding “the theory of exemption of illegal” and provides more deep economic viewpoints based on three economic models, which are “market failure”, “interest balance”, “efficiency maximization”, for the foundation of fair use doctrine. Hopefully, it could make up the defects of imperfect reasoning in judicial judgment. This article also argues that the economic theory behind article 65 of Copyright Law should be the interest-balance model.