Les questions préjudicielles interrogent l’office du juge administratif qui les formule.Accessoires du procès au principal, elles pourraient être considérées comme des questions annexes etsecondaires. Cette étude de contentieux administratif, fondée sur l’analyse systématique de lajurisprudence administrative, vise à démontrer le contraire. Remarquables tant par leur variété que parleurs incidences sur le procès, les questions préjudicielles restent souvent perçues comme descomplications de procédure inutiles visant à retarder la résolution du litige. Cette étude prend le partid’expliciter comment le juge administratif au principal en vient à construire une question préjudicielle,et quel en est le fondement juridique. De ce point de vue, si les parties au litige jouent bien souvent unrôle essentiel dans le relevé d’une exception, c’est en dernière analyse, le juge au principal qui détientle pouvoir de formulation de la question. Par ailleurs, la mise en oeuvre des questions préjudicielles,traditionnellement présentée comme paralysant l’office du juge, apparaît sous un nouveau jour. Loind’immobiliser l’office du juge au principal, l’étude minutieuse du droit positif révèle les importantspouvoirs que possède encore le juge a quo dans la maîtrise du procès dont il est compétemment saisi.Enfin, la réception par le juge a quo de la décision préjudicielle correspond à un partage de lasouveraineté juridictionnelle impliquant l’édiction d’un acte juridictionnel issu d’un processus decodécision. Cette étude livre un éclairage sur le fonctionnement et la complexité d’un mécanisme icitraité sous l’angle de l’office du juge lorsqu’il se place en situation de juge a quo. Elle permetégalement d’envisager les principales problématiques juridiques relatives à la fonction juridictionnelle. / Preliminary issues challenge the role of the administrative law judge who formulates them.They are regarded as being accessory to the principle case at bar. They may even be perceived assecondary issues. This study of administrative litigation, based on a systematic analysis ofadministrative case law, aims to establish the opposite. Preliminary issues are characterized by theirdiversity as well as by their influence on the lawsuit, however, they are often perceived as useless andcumbersome procedural complications aiming to delay the resolution of the dispute. This study aimsto explicit the process by which the administrative law judge builds a preliminary issue and what is thelegal foundation of such an issue. From this angle, albeit the fact that the parties to the main disputeplay an essential role, it is the judge, who mainly retains the power to formulate the preliminary issue.This analysis challenges the traditional portrayal of preliminary issues as paralyzing the judicial“office”. To the contrary, far from immobilizing the “office of the judge”, an in depth study of positivelaw reveals the extensive powers that the judge a quo possesses with regards to the case at bar.Finally, the reception by the judge a quo of the preliminary ruling corresponds to a sharing of juridicalsovereignty implying the passing of a juridical act emanating from a process of co-decision. Thisstudy aims to shed light on the functioning and the complexity of a mechanism rarely examined fromthis angle. This study equally allows for an exploration of the main legal issues relating to the judicialfunction and the “Office” of the administrative law judge when placed in the situation of judge a quo.

本論文主要在討論，先決之爭點與「爭端解決規則與程序瞭解書（DSU）」第六條二項（成立小組請求）間之互動。 首先，作者區別成立小組請求兩大要件，分別為：敘明系爭措施及提供法律根據已釐清系爭案件。 其次，在此架構下，本文進而從近來所發生之四十七個爭端解決案件中，分析上訴機構對兩要件之認定標準的發展。本文發現，爭端解決小組及上訴機構透過放寬先決爭點認定標準之結果，會降低成立小組請求之明確性。同時，本文也蒐集相關實證統計資料，藉以呈現先決爭點如何影響DSU之功能。經由歸納後，本文認為，當前先決之爭點的負面影響大於正面影響。 再者，儘管先決爭點有上述問題，作者一方面仍肯定先決之爭點的正面功能，並認同爭端解決實務放寬認定標準之趨勢；另方面，則嘗試提出若干工具以避免上述負面影響大過正面影響。 最後則提出第六條第二項之修法建議。 關鍵字：爭端解決規則與程序瞭解書（DSU）第六條二項、成立小組請求、先決之爭點 / This thesis focused on the interaction between the preliminary issues and Article 6.2(panel request) of Understanding on Rules and Procedures Governing The Settlement of Disputes(DSU). First, the author distinguished the two main requirements of panel request: identify the specific measures at issue, and provide a brief summary of the legal basis of the complaint sufficient to present the problem clearly. Secondly, with the two requirements as framework, the author started to scrutinize how preliminary issues affected recent 47 dispute settlement cases and analyze its implication. Then, it was observed that the Dispute Settlement Panel and the Appellate Body were broadening their review standards as to preliminary issues, which would then lead to reduce the precision of panel request. Meanwhile, this thesis collected relevant statistic data to show how the preliminary issues affected the current DSU function. Then, it was observed that the preliminary issues, so far, had strong negative effects and few positive effects on the dispute settlement system. Moreover, the author, on the one hand, recognized the function of preliminary issues and viewed current dispute settlement practice as good trend with some deficit; and, on the other hand, tried to propose some useful tools to prevent the negative effect to overcome positive effects. And eventually, proposed revision of Article 6.2 of DSU. Key words: Article 6.2 of Understanding on Rules and Procedures Governing The Settlement of Disputes (DSU), panel request, preliminary issues