本研究旨在探討共同零售通路中，品牌力量大小不同的雙佔製造商的廣告最適策略。強勢製造商相對於較弱勢製造商有較強的品牌廣告力，並有較多的忠誠顧客。市場當中存有兩種製造商的忠誠顧客及游移顧客。製造商可以透過執行產業廣告吸引新的游移顧客來擴大市場規模，或是執行品牌廣告使部份游移顧客轉移成忠誠顧客。首先，由製造商選擇完廣告策略後，再由零售商制定兩產品的零售價格，最終利潤的分配根據廠商對總通路利潤的邊際貢獻與議價能力而定。我們採用Hotelling模型，在正規條件下得到以下重要結果：一、當強勢製造商執行品牌廣告時，除了強勢製造商自身利潤提升外，整體通路利潤與對手的利潤皆提升；當弱勢製造商執行品牌廣告時，整體通路利潤、對手利潤、零售商利潤皆下降。二、當廣告成本小且產業廣告吸引的人數不夠多時，在均衡時強勢製造商執行品牌廣告而弱勢製造商執行產業廣告；然而，隨著產業廣告吸引的人數增加且廣告成本較高時，在預期對手執行品牌廣告時，只有強勢製造商選擇執行產業廣告來擴大市場。三、由於共同零售通路可以緩和製造商之間的價格競爭，隨著消費者對於產品的願付價格越高，製造商執行品牌廣告的誘因相較於垂直整合通路將越強。四、在一些條件下，共同零售商議價力的上升有助於提升整體通路利潤。

This paper analyzed the optimal advertising strategies of duopolistic manufacturers who distribute their products with different brand power through a common retailer. The leading manufacturer has a stronger brand with larger loyal base than its rival. The market consists of two loyal segments and a segment of switchers. Manufacturers can expand the market by conducting generic advertising and attracting new switchers, or transforming current switchers into their loyal customers by conducting brand advertising. The manufacturers first choose their advertising strategies and the retailer chooses the retail prices for the two products. The division of the whole channel profits depends on the marginal contributions of the two brands and the bargaining powers of the two manufacturers. Using the Hotelling model, we derive the following results under some regularity conditions: (i) When the leading manufacturer conducts brand advertising, not only his profit but also his rival's and the whole channel profits will increase; when the weaker manufacturer conducts brand advertising, the whole channel profit his rival's and the retailer's profits will all decrease. (ii) When the advertising cost is small and the number of new users attracted by generic advertising is moderate, in equilibrium the leading manufacturer conducts brand advertising and the weaker manufacturer conducts generic advertising. However, with the increase in the number of new users generated by generic advertising, a higher advertising cost makes only the stronger brand choose generic advertising when expecting his rival choosing brand advertising. (iii) The higher the willingness to pay of consumer for products, the stronger the manufacturers' incentive to conduct brand advertising in the common retailer channel despite it is not so in an integrated channel. (iv) Under some conditions, the increase in the power of the common retailer relative to the manufacturers may enhance the channel profits.