中游廠商面臨產業結構屬於獨寡占的上游廠商，兩者之間由於中游的經濟規模小於上游形成不對稱組織交易，再者中游廠商與上游存在依賴關係，前者需要後者提供原物料或技術服務以滿足下游顧客需求。本研究利用策略行銷成本架構(4C analysis)，並針對國內各大產業之中介廠商為研究對象，包含電機機械通路產業、半導體設計製造業以及旅遊資訊服務業等產業進行深度訪談。此獨寡占上游─中游─下游情境中，分別解釋產業鏈中的從屬關係。 首先是權力處於相對弱勢的中游廠商與上游的交易關係：中游廠商看似被上游供應商套牢陷入的狀況，但除了存在專屬陷入成本外，影響該交易關係尚存在外顯單位效益成本以及道德危機成本。接著，中游廠商為了與上游持續交易的目的下，採取的策略成本選擇為降低外顯單位效益成本，以及提高上游廠商對於中游的專屬陷入成本以達到與上游持續交易的目的，另一方面，順應此不利環境下，中游廠商滿足下游需求的做法有降低外顯單位效益成本、資訊搜尋成本、道德危機成本以及提高專屬陷入成本的方式。最後一部分為中游為減少對上游廠商的依賴，對於上游或下游投資抵銷性資產，使中游廠商提高本身的議價能力，對於上游廠商的依賴程度獲得減緩。 / In comparison to monopoly or oligopoly up-stream suppliers, mid-stream firms has smaller scale in terms of revenue, the transaction between the two can be described as asymmetric interorganizational relationship. Besides, the mid-stream firms depend on its supplier for key material or services, in order to fulfill the demand of their down-stream customers. This study focus on the monopoly/oligopoly upstream supplier to mid-stream firms to down-stream customer chain, interviewing mid-stream firms in different industries including dealer in electrical machinery industry, semi-conductor industry and tour agent and delve into the relationships between these characters by 4C analysis structure. First of all, the study took a closer look at the relationship between the mid-stream firms and their suppliers; the formers have an inferior bargaining power position and seemed being locked up by the latters, as known as cost of asset-specificity. But we also found that over cost per utility and cost of moral hazard would also be considered by the mid-stream firms. The mid-streams took some actions in order to assure the continuous cooperation with the suppliers, and under this circumspect they will also make efforts to save down-stream customers. We found that the 4C analysis can explain the strategies taken by those mid-stream firms. Finally, the mid-streams would like to reduce the control of the up-streams, so they would put resources in establishing offsetting investments to accumulate their bargaining power to the suppliers, to mitigate the dependence.