This paper is a study based on surveys conducted for Tokujin-do at Koishikawa Korakuen Garden, a site designated as a Special Historic Site and a Place of Special Scenic Beauty, located in Bunkyo Ward in Tokyo. Tokujin-do was reroofed and partially repaired from December 2012 to March 2014 during which time traces and marks left in the building were examined and historical materials were analysed.<br> A separate study discusses Tokujin-do from a historical point of view while also investigating the changes made to the alcove and the images which it enshrined. However, previous studies which focus mainly on the early modern period have not examined changes that occurred thereafter. Furthermore, there is no reference to an architectural examination of the building other than its alcove. Since the latest surveys conducted for the building have revealed that parts of the roof and some of the fixtures had been renovated during and after the late modern period, this study will analyse the survey results and summarize the changes made to Tokujin-do from its construction to the present.<br> Based on this study, the changes made to Tokujin-do can be summarized as follows. (1) Tokujin-do was constructed during the period of 1665 and 1669 (Kanbun 5-9) to enshrine the images of Tai Bo, Boyi and Shuqi. It is possible that vegetal materials were used for the roof covering. (2) During the period of 1700 and 1702 (Genroku 13-15), the building changed its name firstly to Koshi-do, then to Shaka-do. Tile roofing was used at this point. (3) After 1718 (Kyoho 3), the name was changed to Hachiman-do and the alcove was made smaller. This was also when the images of Tai Bo, Boyi and Shuqi were transferred to a different place. (4) In 1820 (Bunsei 3), when the building was renamed Tokujin-do once again, the frontage of the alcove was widened to hold the newly created images of Boyi and Shuqi. Thereafter, the building and images were partially repaired during the Edo period. (5) During the first half of the Meiji period (1868-1887), extensive repair works took place, which involved the dismantling of the roof truss, frame and its surroundings as well as the floor face. The roof covering was made with shingles. (6) From then on until this day, the building has been repeatedly reroofed using different roofing material such as iron sheets and copper sheets.<br> This study examines Tokujin-do from historical sources as well as from surveys and an analysis of the building itself. The findings from the paper will not only help explain the importance of Tokujin-do in relation to Confucianism architecture, but should also contribute to further studies of garden design history as well as in the fields of politics, philosophy and religion.