등가성 장애에 관한 연구 -독일법의 논의를 중심으로-

Contract extinction is the ultima ratio that could be allowed in a casewhere proper contract benefits do not exist to each contracting party anymore. Contract extinction is determined by testing whether contractbenefits exist or not. Contract extinction include two types: rescission ofcontract and cancellation of contract. Rescission is to aim to putcontracting parties in the original positions before contract, consideringchanges of circumstances. Rescission applies only to a contract that couldbe performed in a short period of time. On the other hand, cancellation is to terminate contract relations in thefuture in a contract that should be performed continuously for certainperiod of time. However, the principle of pact sunt servanda should beobserved. The change of contract on special conditions must be recognizedonly in an exceptional case. Contracting parties are required to performoriginal obligations. Equivalence of contract is breached if a change ofcontract is allowed. Equivalence obstacle belongs to risk of contract whichcontracting parties should undertake. Amendment of equivalence obstacle,therefore, has exceptional characteristics. Two circumstances that couldlead to amendment of contract are 'change of circumstances' in contractand 'important circumstances' in cancellation. This research is to study the legal regulation on contract extinctionfrom the point of view of change of contract. Especially, the 2009 civilcode proposals include the general regulation on cancellation and theprinciple of change in circumstance. This study reviews the concept of equivalence obstacle, the standard of equivalence obstacle, and especially,equivalence obstacle as a justification of cancellation of contract.