本文建立一個垂直相關市場的理論模型，於存在可自由進出的中間財 市場下，分別探討最終財廠商在浮動價格契約與固定價格契約下的研發決 策及其對中間財價格的影響。本文發現，在浮動價格契約下，當中間財廠 商可以自由進出市場時，無論最終財廠商之研發是否會產生外溢效果，均 不會影響中間財價格。再者，在中間財市場為一可自由進出的結構下，下 游廠商研發投入會高於在上游廠商家數外生給定為一家的情況。最後，若 廠商從事研發會產生外溢效果，則隨著外溢效果增加，儘管最終財廠商的 研發投入量會隨之減少，但其產量卻會呈現先增後減的變化。上述發現均 與過去相關文獻所得之結果明顯不同。;This paper establishes a vertical-related model in which intermediate goods market is free entry to discuss the research and development (R&D) of downstream firms and the impacts of downstream firms’ R&D on the price of intermediate goods under floating price contract and fixed price contract. The major findings of this paper are that: first, under the floating price contract, the price of intermediate goods won’t be affected by the R&D decisions of the downstream firms when the intermediate goods market is free entry, regardless of R&D spillovers; second, the amount of R&D under the case that the intermediate goods market is free entry will be more than that the intermediate goods market is monopoly; last, if there exists R&D spillovers, the R&D level of downstream firms will decreases but the quantities will increase at first then decrease with the spillover effects. The above results are quite different from the previous literatures’ conclusions.
