Abstract
During the Showa period of prewar days from the end of Taisho period (1920th-1940th), Jiun MASUDA led a bridge design office, and designed many bridges. However, the organization of this office is not well known nor whether Masuda played a principal role in all bridge design works. Many design documents and drawings of Masuda's office, which bear dates and signature of the person in charge were discovered in Public Works Research Institute (PWRI), and investigation of these documents revealed the organization and activities of the office. As a results of the investigation, there were about ten design staff in the office, and their names and the structures they designed were clarified. Among them, Kenzo INABA was as skillful an engineer as MASUDA, and it became clear that INABA had a major position of the design office.
