本文檢討黃鴻和麥朝成教授差別取價模型中的一個特例。假定 (甲)住在 不同地區的消費者有著相同的線型需求函數，(乙)廠商可以自由選擇設廠地點。 我們證明了獨占廠商單一出廠價格的產量等於差別取價的產量。但是單一出廠價 格的福利水準卻低於差別取價的福利水準。前一結果和貝克曼廠址固定模型的結 果，不謀而合。後一結果卻和貝克曼的結果大不相同。本文的分析顯示設廠地點 對於空間取價效果的影響是不可忽視的。

　　　　　This note examines a special case of Hwang and Mai'smodel (1990). It assumes that demand functions are linear and identical in different locations, and shows thata monopolist's output under f.o.b. pricing is identicalto that under discriminatory pricing. But the welfarelevel under f.o.b. pricing may be lower than that underdiscriminatory pricing. These results indicate that the Beckmann proposition on the output effect of spatialprice discrimination holds but the Beckmann proposition on the welfare effect may not hold when the plantlocation is a choice variable.