本文以國內麵粉業者聯合獨占市場案為研究標的，利用Fershtman-Gandal模型及公平會之統計資料，進行實證分析，得出兩項主要結論。第一，麵粉業者確有透過聯合行為決定價格及產出。第二，業者為爭取市場配額對產能所為之過度投資，將使麵粉業者成本增加，從而使聯合獨占解之利潤，反低於數量競爭古諾解之利潤，顯示損人不利己之聯合行為的確有可能存在。

This article uses Fershtman-Gandal model and TFTC (Taiwan Fair Trade Commission) data to investigate the flour cartel case. The empirical evidences indicate that collusion indeed exists in the flour industry. Besides, the expenses of overinvestment increase flour firm’s total production cost. Thus, the collusive equilibrium profits are even lower than the noon-cooperative Cournot equilibrium profits. The firms are better off not colluding.