The study describes an analysis on historic drawings about OKURA MUSEUM OF ART designed by Chuta Ito. There are 43 drawings, these drawings are original drawings, blue prints, microfilms. Only one sheet of drawing has a signature by Chuta Ito. 14 architectural drawings have a common title block. These are the final drawings. There were somehow related to Chuta, and definitely or probably designed by Chuta. These 14 final drawings are not a reduced scale. So it is impossible to build the museum building with these final drawings. I assume there was a backup by Okura Doboku in the construction.