Zeami is regarded as the founder of Noh today and was also a theorist who wrote 21 books emphasizing the necessity of unifying singing, dancing and performing when discussing involved ideal Noh and the training. In this paper, I attempt to clarify the meaning of his theory by focusing on the concept of "rhythm" which proves to be an important factor for achieving unity and I examine how Zeami addressed the problem of learning. Chapter [I] sketches out "Nikyoku-Santai" which we can think of as a curricurum of training. Chapter [II] deals with "Nikyoku" (singing and dancing) and points out that mastering "Nikyoku" means forming an articulated body which can express the "rhythm" permiating both singing and dancing. Chapter [III] discusses "Santai" (the three performance models) and points out that this training aims at modifying the "rhythm" into three styles of existence by establishing three different relationships between mind and body. Chapter [IV] examines "Knowing the law of Johakyu" which a Noh actor must comprehend after mastering the skills mentioned above. By advancing through these stages, the "Noh-body", which realizes the true nature of Noh, is established. The Conclusion discusses the significance of Zeami's theory to "learning" in general, especially the importance of "body" formation which integrates the "rhythm" of various media codes