本文建立一個考慮中間財市場的垂直耐久財模型，探討中間財的垂直力量會如何影響耐久財廠商的行為決策，並且進一步考慮市場結構的改變，中間財市場的存在對耐久性決策所產生的效果為何。本文發現耐久財廠商數的增加，除了Bulow (1986) 所提及，廠商有誘因提高耐久程度來達到打擊對手的效果，中間財價格也是影響耐久性決策的重要因素，發現下游廠商對於耐久程度的選擇隨著競爭對手的增加有先升後降的趨勢。另外，透過模型比較，本文得知，當耐久財廠商數較少的時候，中間財的市場力量會使得耐久財廠商提高產品耐久性；反之，當耐久財廠商數較多的時候，中間財的垂直市場力量會使得耐久財廠商降低產品耐久性。;In this paper, I created a vertical durable goods model considering the intermediate goods market, and discuss how the market power of intermediate goods will affect the behavioral decision of the durable goods firms. Moreover, considering the existence of the intermediate goods market, how the market structure will change to affect the decision of durability. I found that when the number of durable goods firms increase, including Bulow (1986) said that manufacturers have incentives to improve the degree of durability to strike opponents, the price of intermediate goods is also an important factor to affect the durability decision. According to my results, the decision of durability by downstream will rise at the first and then down by the number of downstream manufacturers. In addition, by the comparison of two models, I found when the number of durable goods firms is less, the market power of intermediate goods will induce durable goods manufacturers to improve durability; on the other hand, when the number of durable goods firms is numerous, the market power of intermediate goods will induce durable goods manufacturers to reduce durability.
