網路與科技的快速發展，改變媒體生態分佈，新型態視訊服務進入市場亦改變原有媒體視聽市場結構，對於如何界定市場，透過妥適的分析工具，檢視與評估競爭問題，在國際間備受重視。我國現行法規，無線電視、有線電視與IPTV皆受到不同法源與強度之規管，而網路串流影音服務暫時則無。為維持市場公平競爭，市場界定為後續市場分析與擬定管制措施或政策之前提。本研究採SSNIP市場界定測試方式，從消費者端探討並界定我國付費視訊服務市場，透過問卷調查法，從需求面調查民眾對於有線電視、中華電信MOD與付費網路視聽平台（付費OTT）替代性之態度，並依SSNIP上漲幅度5%及10%不同情境進行價格敏感性測試，分析消費者之消費選擇決策，再以臨界損失法判斷個別市場和聯合後選市場之市場界定。研究結果發現，不論是在SSNIP上漲5%或10%情境下，前述三種產品本身皆無法單獨構成相關市場，而有線電視與中華電信MOD則可界定為相關市場。本研究發現，考量有線電視與中華電信MOD於產品市場層面，可界定為相關市場之前提下，主管機關應可進一步考慮目前由於法規導致之地理市場界限，是否有必要放寬；另基於通盤考量，亦可納入是否該適度鬆綁我國視訊服務市場管制，促進我國視訊服務市場公平競爭。

This study aimed to address the issue concerning whether cable TV, IPTV and paid OTT TV services should be classified as the same relevant market in Taiwan. The approach, small but significant and non-transitory increase in price (SSNIP), was employed as the main method for delineation of relevant market. For the purpose of testing price sensitivity, this study designated two scenarios, 5% price increased and 10% price increased while adopting SSNIP approach to identify consumers’ choice decisions by comparing critical loss and actual loss. Quantitative data were collected via the well-structed questionnaire, and there was total 1068 interviewees responding to our telephones’ investigations. The main findings indicated that none of the aforementioned three products was capable of constituting the relevant market individually, regardless of the scenario where the price rises by 5% or 10%. In this respect, cable TV and Chunghwa Telecom’s MOD (IPTV) were able to be verified and defined as relevant markets no matter 5% price increased or 10% price increased. According to this empirical analysis, cable TV and Chunghwa Telecom’s MOD were considering as the relevant market. Based on the main findings, this study suggested that the relevant policy should be revised concerning the consistent geographic market definition for cable TV and Chunghwa Telecom’s MOD.