COVID-19疫情對契約履行造成全面性衝擊，凸顯現行契約法制在面對重大情事變動時之調整能力與制度界限。本文以租賃產業與公共工程產業為分析對象，檢視我國實務於疫情期間之履約責任運作模式，發現不同產業之契約類型在法律評價上呈現顯著差異：租賃關係多透過情事變更原則進行契約調整，公共工程則多透過不可抗力制度處理履約障礙，其調整重點集中於工期展延及違約責任之減免，而對於疫情造成之履約成本增加，則欠缺完整之法律調整機制，致使相同外在事件於不同契約類型下產生不同之風險分配結果。 本文進一步指出，上述差異並非僅源於契約性質不同，而係現行法制採取不可抗力與情事變更之二元架構，使重大情事變動所引發之契約失衡問題，分別置於不同法律制度下處理，致法律評價欠缺一致性。透過比較德國民法第313條契約基礎障礙制度之理論與疫情期間之適用經驗，本文認為，以契約基礎重大變動為出發點，建立整合性審查思維，更能妥適回應重大公共危機下契約風險重新分配之需求。 基此，本文主張，再面對重大公共危機情境下，我國契約法制宜借鏡德國民法第313條契約基礎障礙制度之理念，由現行「不可抗力」與「情事變更」之二元架構，逐步朝向以契約基礎重大變動為核心之審查模式發展，以提升法律適用之一致性與可預測性，並強化契約法因應未來重大公共危機及其他不確定風險之調整能力。;The COVID-19 pandemic has imposed a comprehensive impact on contract performance， highlighting the adjustment capabilities and institutional boundaries of the current contract law system when facing major changes of circumstances. Focusing on the leasing and public works industries， this thesis examines the operational models of performance liability in Taiwan′s judicial and administrative practice during the pandemic. The analysis reveals significant disparities in legal evaluation across different contract types: while leasing relationships frequently utilized the doctrine of change of circumstances for contractual adjustment， public works primarily relied on the force majeure mechanism to address performance barriers. In public works， adjustments were heavily concentrated on the extension of time (EOT) and the mitigation or exemption of default liability. However， a comprehensive legal mechanism remains lacking to address the increased performance costs caused by the pandemic， resulting in divergent risk allocation outcomes for identical external events under different contract types. This thesis further points out that such disparities stem not only from the distinct nature of the contracts， but also from the binary framework of force majeure and change of circumstances in the current legal system. This framework processes contract imbalances triggered by major crises under separate legal regimes， leading to a lack of consistency in legal evaluation. By conducting a comparative analysis of the doctrine of "interference with the basis of the transaction" under Section 313 of the German Civil Code (BGB) and its application during the pandemic， this thesis argues that establishing an integrated analytical framework based on the fundamental change in the basis of the contract can more appropriately address the need for contract risk reallocation during major public crises. Accordingly， this thesis proposes that when facing major public crises， Taiwan′s contract law system should draw inspiration from the concept of Section 313 of the German Civil Code. The current system should gradually transition from the binary framework of "force majeure" and "change of circumstances" toward an analytical model centered on major changes in the basis of the contract. This shift aims to enhance the consistency and predictability of legal application， thereby strengthening the adaptive capacity of contract law to respond to future public crises and other uncertain risks.
