轉用物訴權孕育於古代羅馬法，歷經優帝羅馬法大全、中世紀羅馬 法繼受、歐陸早期普通法的擴張運用、18 世紀普魯士普通法及奧地利 民法之繼受，到 19 世紀德國潘德克頓法學時代極盛而衰、德國民法立 法者之唾棄。法國民法在無不當得利一般規定的情形下，判例透過轉用 物訴權發展出不當得利一般法則，日本民法雖不當得利一般規定，判例 卻也有條件地承認轉用物訴權。我國民法並無轉用物訴權的明文，轉用 物訴權並非具有獨立要件及效果的法律制度，也不是足以正當化利得返 還請求之法律思想或法律原則，而僅是契約相對性原則的例外表現，即 基於一定原因，例外地允許契約當事人（X）向相對人（M）之債務人 （Y）直接請求利得返還。此特殊原因有兩類，第一、受讓人無償而獲 得利益與原權利人保護必要性利益衡量上，認為應優先保護後者；第 二、在事務處理領域，事務之本人是最終承擔事務處理人交易經濟上利 益及不利益之人，在事務處理人無資力時，承認第三人對本人有直接請 求權，並不違反本人、事務處理者及第三人之交易計畫及利益狀態。

The action de in rem verso in classical Roman law had not been an independent action, but a procedural device to deal with the special problems of contracts by sons and slaves. Justinian’s compilers had conceived it as an independent one and applied it to contracts involving free persons. The actio de in rem verso in its extended version was fully recognized by scholars in the usus modernus pandectarum and could be found in the natural law codification of the eighteenth century. The legislators of the German BGB rejected it as part of the law of unjust enrichment. Although the Civil Law in Japan contains no specific provision regarding the actio de in rem verso, the decision of the Supreme Court in 1970 has made use of it as a tool allowing a non-contractual party’s claim. In Taiwan, both legal scholars and court decisions knows very little about the actio de in rem verso. This article shows that the justification of allowing third party to claim on contrat bases may be found in some cases and the idea indicated in the actio de in rem verso may be helpful to solve this problems.