數位時代孕育大數據技術的發展並帶動產業的創新，使用者數據的運用也日益活躍於商業領域，並分別為消費者與事業帶來便利的生活與競爭優勢。然而蒐集、處理、運用等數據價值鏈活動對於市場競爭造成相當的影響，也成為事業為反競爭行為的誘因，而引起競爭法的關注，多國競爭執法機關亦已陸續展開調查或進行相關研究。由於使用者數據涉及個人資訊隱私，更因其係產業創新的動力之一，從而競爭法管制的合適性與必要性一直為爭議性議題，後續延伸出對於現有競爭法架構的相容性疑義。本文透過文獻與案例分析，從使用者數據的特色出發，探討使用者數據於競爭法框架下之爭議，包含與隱私法規的競合問題及衝擊現行制度之因應方式。基於競爭法適度管制的觀點，提出可能評估市場力量的方式與使用者數據可能形成的限制競爭或不公平競爭之風險類型。冀望對於我國公平交易法就此議題之剖析與因應有所助益，迎接數據經濟的浪潮。 / Big data analytics technology evolves rapidly and enhances the pace of the innovation of industries in the digital era. Utilizing user data, which is a sort of valuable assets, becomes more popular in business. The new technology brings consumers fitted products and convenience and creates competitive advantages to firms. However, collecting, processing and analyzing large sets of user data not only benefit the entities in the market but also impact market competition. Competition agencies around the world have engaged in related investigations and research on data and competition. The mainly concerns are whether the amount of user data may build a barrier to entry, and whether firms which control user data in a massive amount or essential to competition may have incentives to abuse their market power to foreclose marker. Moreover, because user data is one factor of fostering innovation and has a strong correlation with privacy, the suitability and the necessity of competition law to regulate data issue is still controversial. If competition law intervenes, we should further consider how to adapt it to the present regulation. By reviewing academic literature and practical cases, this thesis begins with the introduction of characteristics of user data, followed by the analysis of the controversy concerning user data under the framework of competition law, including the trade-off between it and privacy laws and possible adjustment to the present framework. This paper also discusses the way to assess market power and specific types of anticompetitive and unfair competition behaviors. Finally, this thesis concludes with a short remark. Hopefully it can provide some references for further discussion on this issue under the Fair Trade Act in Taiwan.