The study describes an analysis on Taisei Co.’s Gionkaku drawing collection designed by Chuta Ito. He was said to have close friend with Kihachiro Okura (founder of Okura Doboku). Taisei Co. has a large number of microfiche drawings, not original, related to Kihachiro, including some drawings which Kihachiro had Chuta design. Taisei also has 82 Gionkaku drawings, 21 of which were somehow related to Chuta, 8 of which were definitely or probably designed by Chuta. As a result of the analysis, it can said that Gionkaku construction were held, as they exchanged their opinions each other.