臺灣民眾自我防衛的決心，對於我國國防及東亞區域和平皆有重大影響。尤其是在面對可能的兩岸衝突狀況下，了解臺灣民眾的自我防衛意願，與國家安全息息相關。然而，如何解釋臺灣民眾自我防衛決心的差異，在現存的國際關係文獻裡面的討論有限。我們認為，民眾在理性計算是否願意參戰時，過去的從軍經驗是心理上最直接仰賴的資訊，因此從軍經驗的好壞，理論上會影響民眾的自我防衛決心。本文把從軍經驗分成三個面向，包括軍種、覺得軍事訓練對上戰場的有用程度、以及從軍時與長官的相處狀況，並於2018年7月委託政治大學PollcracyLab執行樣本數1001的網路問卷。統計結果顯示，臺灣民眾服役的軍種以及評估受軍事訓練的有用程度，都對自我防衛決心有顯著影響（軍種主要為空軍較高），但與長官相處經驗則沒有影響。另一方面，越年長的世代，越傾向於覺得當年從軍所受的訓練有助於軍事防衛。本文也將在最後提出國家安全相關的政策建議。

What explains Taiwanese citizens’ determination of self-defense? To date, few studies touch upon this issue. We argue that one’s military service experience is an important factor for studying citizens’ willingness to fight and hypothesize that positive experience could be conducive to higher willingness for self-defense as the citizens feel they have the capabilities and preparations for a conflict. We operationalize military service into three dimensions: military branch, evaluation of usefulness of military trainings, and interactions with units’ senior officers. Using an original online survey conducted by National Chengchi University in July 2018, we find: (1) military branch matters-serving in the Air Force leads to higher determination, and (2) positive evaluations of the military training lead to higher determination. Additionally, we also find that the older generations believe that military trainings are effective for real conflicts. Based on the empirical findings, we propose several policy suggestions.