The 'Research report on the Korean architecture(韓國建築調査報告)' is the first investigation and research of the Korean architecture by Japanese researcher. This paper is about Sekino Tadashi's viewpoints of Korean architecture in the 'Research report on Korean architecture'. And the findings are as follows. The investigation of the Korean architecture by Sekino Tadashi was carried out in the concern about the relation between Japanese architecture and Asian architecture, shortly after the research of the history of Japanese architecture started. And following investigation and research about Korean architecture by Sekino Tadashi was mainly focusing on the ancient architecture which he estimated highly in the 'Research report on the Korean architecture'. When he observed each architecture himself, he estimated highly the ancient Korean architecture, of course. And also he estimated highly many architecture of the Koryo and the Chosun period. However, when he estimated Korean architecture as a whole, he had been strongly influenced in the prejudice about Korea in Japan of those days. But this is not originate in his individuality. History research reflects the historical situation that the researcher was placed. The viewpoints of Korean architecture in the 'Research report on the Korean architecture' was produced by the Korean recognition in Japan of those days.