In Korea, the number of involuntary admission of mental illness has increased. Especially, the cases that were conducted the admission by supervisors of mental patients take the biggest portion of the involuntary admission. The involuntary admission as the complementary measure against patient's will falls under the restriction of his/her personal liberty which limits or deprives his/her personal liberty. Anyone has right to enjoy the personal liberty and most countries including Korea have the system to protect the personal liberty. However, the personal liberty is not inviolable right that has unlimited protection. It can be limited in a certain situation. Most countries including Korea provide a personal detention system to protect the public safety and order under the regulation. In Korea, the Mental Health Act allows the supervisor to proceed the involuntary admission of the mental illness patient if the psychiatrist decides that the patient need to be hospitalized for the medical treatment and the society's necessity. Mayors, county headmen, and headmen of a ward may also order the admission of the patients. Moreover, in case of emergency, the suspected patient may be hospitalized with the approval of the psychiatrist and the police. According to the Mental Health Act, for the benefits of the patient and the protection of the public safty, there are positive effects that the patient can have efficient medical treatment and seek to come back to the society by quarantining the patients from the society. In the other hand, the involuntary admission may cause serious violation of the fundamental rights and human dignity which are protected by the Constitution. In particular, the violation of the patient's personal liberty may cause serious problem. Therefore, the appropriate procedure of quarantine is needed to prevent the violation of the personal liberty and the patient's rights. Furthermore, the after-plan of the violation should be prepared for the patients who are violated their personal liberty.