本研究從關係投資的觀點出發結合品牌社群概念，探討國內職棒後援會成員在品牌社群中的關係忠誠行為。研究對象以新莊、新竹、台中、台南、高雄及屏東球場六支職棒球隊球賽現場加油的後援會球迷為樣本，實際有效問卷263份。實證結果發現：後援會成員之品牌社群滿意度與關係投資對社群關係承諾有正向影響；品牌社群替代方案吸引力對社群關係承諾有負向影響；品牌社群關係承諾對品牌社群忠誠有正向影響。此外，社群關係承諾對關係投資與品牌社群忠誠之關係具完全中介效果；但對社群滿意度、社群替代方案吸引力與社群忠誠之關係，則具部分中介效果。本研究管理意涵有四：職棒球隊品牌管理者在活動設計上，應考慮如何進一步維持、並提昇球隊後援會球迷滿意度、加深球隊後援會球迷的關係投資、建立球隊後援會球迷對所屬後援會的關係承諾，以及鼓勵球隊後援會球迷長期的參與。

This research applied both relationship investment model and brand community concept to probe into the domestic professional baseball fans' loyalty to their relative communities. A survey of 263 effective samples from six professional baseball fields was conducted. The results indicate: The satisfaction of brand fans and the extent of investment in developing this relationship positively influence their commitment to the community. The attractiveness of alternative brand communities negatively impacts the commitment. Fans' relationship commitment is positively associated with the community loyalty. This commitment to the brand community completely mediates the relationship between the relationship investment and the community loyalty, and partially mediates the relationships between the satisfaction of brand community, the attractiveness of alternative brand community and the loyalty. The findings provide brand executives insights to convert fans into long-term patrons. We inferred from the results that brand executives in Chinese Professional Baseball League must ensure that the satisfaction of brand community members is fulfilled and their investment and/or involvement into the community activities is enforced. Finally, higher loyalty can be gained through members' further commitment to the brand community.