This paper analyzed the design process and contents of The Saito Ho-on kai Museum.
•At the beginning，It was a building program of The Saito Ho-on kai Headquarters, Tsuyoshi Ogura was a jdging committee of competition. Next year it became a museum program, and design was requested to him.
Design was able to be known 67 Drawings, the Saito Ho-on kai owns.
• In planning, Not only an exhibition but library , hall ,etc were planned. It is positioned as a developmental process of The Museum Architecture which inherited from The National Museum of Nature and Science.