近年來，國人追求健康、愛美等因素而運動風氣蔚為盛行，連帶擴大穿戴型裝置產業發展，越來越多廠商加入。而在競爭激烈的全球市場中，不少廠商以平台經濟模式的建立及善用網路外部性的發展為轉型的策略，其中，如何有效率擴大平台規模及提高顧客黏著度尤其重要。本研究著重於以下三點：個案公司之平台商業模式的運作機制、如何創造不同種類之網路外部性及如何管理網路外部性創造更多效益。 本研究採取單一個案研究法，並挑選從GPS大廠成功涉足智慧型穿戴式裝置且近年來積極轉型之台灣國際航電股份有限公司(Garmin Corp.)，經過研究個案公司平台商業模式與網路外部性的創造及管理，歸納本研究之發現：Garmin透過Garmin Sports平台的管理，建立與外部用戶的關係；並藉由穿戴式裝置的租借與其他廠商合作活動帶動運動市場貿易；再教練培訓為中心出發，提供一套專業、完整的課程，建立平台生態圈，擴大平台規模。 本研究之貢獻在於透過Garmin Sports的案例建立一套平台發展與網路外部性的創造與管理之架構，以期了解透過平台網路外部性發展如何提升使用者價值、為使用者帶來更多效益。歸納出三項因素如下： 1. 專業人士與外部廠商 2. 互補品的發展與資料庫的建立 3. 透過多方用戶的選擇與舉辦活動來管理網路外部性 此外，本研究為Garmin Sports平台成立初期，上線時間較短，部分網路外部性的交互影響研究受限。故建議後續研究，可待Garmin Sports平台運作期間較長，其網路外部性的創造與管理及不同種類網路外部性之相互作用亦會較為明顯。 / In recent years, the atmosphere of physical workout becomes prevalent, which results in the expansion of wearable device industry, causing more and more companies join in this industry. Under such a highly competitive global markets, platform transformation gradually becomes a popular strategy. In the research, our main focus lies on what the platform business model is and how to create and manage different kind of network externality. The case study method is applied for this research. We select Garmin Corp, a GPS corporation which successfully develops wearable devices in recent years and has transformed into a new business model as our research subject. With in-depth case study of platform business model and the creation and management of network externality, we conclude our findings as below: Garmin establishes the relationship with external users and cooperates with other companies through the management of the Garmin Sports platform by leasing wearable devices. To expand the scale of the platform, Garmin provides a set of professional training camp and competitions, so as to establish the platform ecosystem. The academic contribution of this study is to create the structure of developing platform and managing network externality, hoping to bring more value and benefits. The factors are as below: 1. Experts and external companies 2. Complementary products and database setup 3. multi-user selection and managing network externality through events In addition, this study is about the beginning of Garmin Sports platform in which on-line time is short and the interaction of network externality is limited. It is recommended that, for the follow-up research, researches should wait for Garmin Sports platform to operate for a longer period of time. Therefore, the creation and management of network externalities and the different types of network interaction will be more obvious.