근로계약의 무효･취소와 해고의 쟁점 ― 판례를 중심으로 ―

In December 2017, the Supreme Court decided that labor contract is civil contract, so if there is a reason for invalidation or cancellation in the contract, the parties concerned can claim the nullification or cancellation of the contract and extinguish the legal effect of the contract. However because it is not reasonable to deny retrospectively the effect of the labor provided by the employee in accordance with the contract, the Supreme Court decided that the cancellation of labor contract does not take effect on the legal relationship formed on the basis of the labor of the employee already provided before the cancellation. The above decision limited the retroactive effect of the cancellation of labor contract on the labor relationship. However, it overlooked the fact that the cancellation of labor contract under civil law actually has the nature of dismissal under the labor law, as a unilateral expression of employer's intention to terminate a labor relationship. In this regard, this paper examines the legal concept of dismissal in labor relationship, and analyzes nullification and cancellation of labor contracts in the perspective of labor law jurisdiction. In labor relationship, employer's words are order and instruction to employees, and employees are obliged to follow employer's words. Employees' words do not have legal power but employees' works have legal protection against employer's words. The reason why employer's cancellation of labor contract does not have a retroactive effect in labor relationship is that it is impossible to reverse the labor completed by employee.