In today's mass democracy society, political party takes charge of important role in politics. Without democratization of political party itself, it is impossible to put into action democracy. Political party works very effectively to realize democracy, but it also can be effectual means to destroy democracy. So political party shall call for internal democratization of each political party itself. People's variety opinions are put together and changed the national will by political party. These are political party's key functional roles. To perform this job well, internal democratization of each political party is getting more and more important. As political party exercises political leverage extensively, internal democratization of each political party is not only for political party itself, but also for national order. There are two ways to give shape to internal democratization of each political party. One is to make political party's internal organization democratically and the other is to do political party's activities democratically. Political party's internal organization which is composed democratically is putting emphasis on autonomy of expressing political party members opinion. And the delivery system of their opinions shall be bottom up and not top down. Political party's activities is based on democratic decision-making processes which is existed between political party members. So it is important to secure autonomy of expressing political party members opinion. To build political party's democratical internal organization, the proper legal status for each member of political party shall be guaranteed. Political party constitution and platform shall be enacted and made public. To work political party's activities democratically, political party's public nomination for the public office candidate shall be democratic. But first in importance is that internal democratization of each political party comes true effectively when political party and people work together and make efforts together.