It is said that Yoshino Sakuzo was a standard-bearer of the democracy of Japan. However, it is assumed that it takes advantage of an expansionist current of the times in the youth, and nationalism speech and behavior was done by him. A current research is exaltation of the nationalism done when he is young and it is insisted that thought be fundamentally changed. I wonder whether the nation was existence that can be thrown away however for Yoshino. No, it is not so. Even if the insistence was changed for Yoshino according to the change in the situation, the nation outlook that existed in the basis was immovable. In this thesis, whether Yoshino really changed thought is verified through the key words. These are "Nation State", "Constitutionalism", and "Election and party politics". Moreover, there are "Modernist", "British type monarch system", and "Security" importance in "Constitutionalism".
