If we want South & North Korea unification, we must study North Korean’s legal system. In a view of the internal-contextual approach, we have to understand Juche Ideology and Juche’s legal theory through North Korean’s language. This article describes Juche Ideology and Juche’s legal theory, especially, ① the social being’s nature: the self-reliant, the creative, and the conscious, ② the social life for the collectivism: in the economical life, cultural-ethical life, political life, ③ the principle of equality and comradeship as a collectivist morality, ④ the importance of the instruction and organization programs, ⑤ the politics through the virtues of benevolence and excellence, ⑥ the socialist democracy, ⑦ the methods and forms for the socialist democratic operations against the bureaucracy, ⑧ the limit of the collectivist morality and the need of the law, ⑨ the functions of the law: the regulative, the executive and the cultivative function, ⑩ the rule of law for the socialism, ⑪ the collectivist liberty and the human rights, ⑫ the legal life for the socialism, ⑬ the collectivist legal reasoning. In spite of these works, this article has a problem not to describe the ideology of Great Leader.