Architect and architectural historian. The second son of ITO Yujun, feudal retainer of the Yonezawa domain. Graduated from the College of Technology of the Imperial University of Tokyo in 1892. He then went to graduate school and studied architectural history. He became a professor at the College of Technology of the Imperial University of Tokyo. As the first Japanese architectural historian, he discovered the Yungang Grottoes in China and constructed a system for the history of Eastern architecture. He also designed Heian Jingu Shrine and Tsukiji Hongan-ji Temple. In 1928, he retired from the Imperial University of Tokyo and then taught at Waseda University and the Tokyo Institute of Techology, training many architects. Received the Order of Culture in 1943.