本文建立一個兩期獨占耐久財模型，討論廠商生產的邊際成本對其研發投資與生產行爲的影響。主要的研究結果爲：第一、在相同的條件下，邊際生產成本較高之廠商其研發強度較低。第二、在考慮研發下，若跨期折現因子較大時，生產邊際成本上升會使獨占廠商第1期產量上升。這是因為耐久財獨占廠商雖面對時間不一致的問題，但邊際生產成本較高的廠商，其所面對時間不一致的問題較小所致。第三、當獨占廠商具有承諾能力時，他將不進行研發，同時只在第1期銷售耐久財，以迴避寇斯猜測(Coase's conjecture)的問題。

This paper builds up a two-period durable goods model to analyze the impacts of marginal cost on innovation intensity and production behavior for durable-goods monopolists. The results show that first, if the marginal production cost is higher, the innovation level will be lower. Second, when the discount factor is higher, an increase of the marginal production cost will raise the outputs of durable goods in the first period. This is because each durable goods monopolist faces the time inconsistent problem. However, the time incon­sistent problem for a monopolist with a higher marginal production cost will be less serious. Finally, a monopolist with commitment power will choose no innovation and will only sell durable goods in period one to avoid Coase's conjecture problem.