關於不當得利之成立，受利益與受損害間須具關聯性，此關聯性之判斷標準，傳統上不問不當得利之類型，均以因果關係作為判斷，於晚近，學者認為在給付型不當得利，一方基於他方之給付而受利益，是否致他人受損害，應以給付關係取代因果關係作為判斷標準。於三人關係不當得利案例類型，以給付關係作為判斷標準，更有助於不當得利當事人之釐清。本件地方法院與高等法院判決先後以直接因果關係說與間接因果關係說檢視本案受利益者與受損害者間財產損益變動之關聯性，之後歷審法院始以給付關係取代因果關係作為判斷標準，本文將探究以何者判斷標準決定三人關係不當得利之當事人始為妥適。

Regarding the establishment of unjust enrichment, there should be connection between the benefits and losses. Traditionally, the causation is applied to determine the connection between the benefits and losses. In recent years, scholars believe that it should replace the causation by payment relationship to determine the connection between the benefits and losses. In tripartite relationship of payment, determining the connection between the benefits and losses by payment relationship helps in clarifying the parties of unjust enrichment. In this case, district court determines the connection of benefits and losses by direct causation, and high court determines such connection by indirect causation. Afterwards, the courts replace causation by payment relationship to determine the connection between benefits and losses. This article intends to analyze which criterion could be used to properly determine the parties of unjust enrichment in tripartite relationship of payment.