The purpose of this article is to study modernistic elements of Miyosi Tatsuzi' poetry chiefly on his 『SOKURYOUSEN(測量船)』『NANSOUSYU(南窗集)』『KANKASYU(閒花集)』『SANKASYU(山果集)』. Through this study, I could reach to the conclusions as follows: Most of all, the distinctive modernistic elements shown in his intellectualistic poetry are very avant-garde and modern-oriented only in the perspective poetic forms. That is, they are various experiments and explorations toward poetic forms and a challenge to new poetic style, casting off existing poetic forms as well. Of course, he didn't try to destroy the framework of Japanese traditional poetry and didn't allow for any destruction in poetic context. However, it is clear that the emotion shown in his more lyric poems is controlled and that abstractive and intangible images are clearly conveyed to the readers in visual and audible ways. It is the very attraction of Tatsuzi's intellectualistic poetry. Actually, he developed French poetry into his own unique intellectualistic poetry based on excellent wit, a sense of humor and talent acquiring from Japanese traditional poetry.