Since the Judgment of the Supreme Court in 1995, the idea that 'Tolerance Theory' is right and that 'Prohibition Theory' is wrong has been debated continuously. Therefore, this paper explores both views. First of all, I researched 'Prohibition Theory', 'Tolerance Theory', and 'Request Theory'. Next, I questioned the Judgment of the Supreme Court dated Feb. 28, 1995 critically. Finally, I put forward a way to solve the problems of foreigner suffrage in municipalities. In conclusion, I justified why I think 'Prohibition Theory' is appropriate. Therefore, I think the problems with the naturalization of foreigners of permanent residence should be solved by the political consideration such as the amelioration of the condition for naturalization.