The study for the eunuches and their political and social effects during the Chosun Dynasty(朝蘇王朝) has been rarely researched until now. One of the many reasons is that the Chosen Dynasty was based on the Confucian political and ethical system and its society. And so, Only one class would dominate in this system, which was called to Yangban(兩班), first class in the society. At the early years of the Chosun, the eunuch's system was hardly kept in order, so followed the Goryo' s. During King Taejong(太宗) of Chosun, he wanted to prohibit the eunuch from getting a official post, tried to change the authorized official's dress, but it was not in force. During King Sejong(世宗), he limited the eunuch to delivering the King's order. During King Sungjong(成宗) he clearly divided the eunuch from the general officials. At this times, an eunuch who delivered the King's order was sometimes identified as the King. But though, the policy that local gentry had carried out during King Joongjong(中宗) made the status and power of the eunuch dwindled. Now we generally recognize that they were divided from the general officials and were banned from marriage. The eunuch's system at Chosun Dynasty had been steadily kept in order since the late years of the Goryo. Their tasks had limited to preventing the political intervention and to working inside the Court. And then, the number had growly increased and the system also been stabilized. As mentioned above, they were indispensible for the King and essential to succeeding to the Dynasty and the throne.