動機의 錯誤에 관한 새로운 理解

The most important controversy over characteristics of legal act is the controversy over characteristics of mistake, and mistake of motive lies in the center of mistake controversy. Korean Civil Act §109 does not prescribe mistake connecting with motive. For this reason, various theories about relation between §109 mistake and mistake of motive are put forward. The Supreme Court holds that, in order to revoke a legal act for the reason of motive mistake, that motive must be manifested and included in the content of the legal act with an exception where a party's will to conclude the legal act is decided or prompted by the other party's unfair means. The Supreme Court's reasoning is severely criticized by various grounds. But this article agrees with the Supreme Court's standpoint principally. The writer's approval based on the following ground. : Permission of revocation by the reason of motive mistake compels the other party to alter the content of the concluded legal act. And the writer adds that the manifested but not included motive should be treated as rejected to be the content of the legal act. Other topics treated in this article is : ① the relation between mistake of motive and the other sort of mistakes, ② whether the other party's knowledge or knowledgeability is an undescribed requisite. The writer agrees with the negative assertion.