本文利用一垂直差異化模型討論當市場僅存在代理商與平行輸入者時，代理商在面對不同的市場競爭型態下，會如何改變其願意提供給消費者的售後服務。其後進一步假設該市場開始出現仿冒，且消費者無從分別平行輸入品與仿冒品之真偽，探討此時代理商願意提供的售後服務將有何改變。本文的主要結論如下。當市場僅存在代理商與平行輸入者，代理商所提供之服務會比其獨占時要好，且Bertrand競爭下的售後服務優於Cournot競爭時的情況。若市場同時出現代理商、平行輸入者與仿冒者，無論競爭型態為何，仿冒的出現都讓原本只和平行輸入者競爭的代理商利潤增加、願意提供的售後服務減少，唯Bertrand競爭下的服務依舊優於Cournot競爭。本文發現仿冒者此時對代理商而言是有利的存在，有別於一般文獻多認為仿冒必然損害正版廠商利潤的看法。

This thesis applies a vertical differential model to discuss how the distributor may alter their service to the consumers in different types of market competition when there are only distributor and parallel importer in the market. Furthermore, we analyze how distributor may change their service when the piracy exists in the market. The main conclusions of this thesis are as followed. If there are only distributors and parallel importers exist in the market, the distributor will offer a better service than it does when it monopoly the whole market. In this case, the service in the Bertrand competition is still better than that of the Cournot competition. If the piracy 、distributor、and the parallel importer all exist in the market, the existence of the piracy increase the profit of the distributor while decrease its service in all types of competition. While the service in the Bertrand competition remains better than that of Cournot competition. We find that the existence of piracy is beneficial to the copyrighted firm.

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