Shimojo Masao(下條正男) take charge of the chief of “Takeshima Issue Study Group‘ under the control of general affairs department of Shimane-ken of Japan. His study on Dokdo has been the theoretical base of Japanese government for Dokdo sovereignty insistence. However his study was not based on the correct historical fact but on the false proof to justify Japanese Dokdo acquisition. One of the clear instance of his false proofs revealed in his paper 「Thinking of Korea․Japan's visual, Takeshima issue」 in the report work of 『A survey report about Takeshima Issue』 which was published by Web Takeshima Research Center in July 2007. He insisted false historical material at the interpretation of‘Park Sae-dang(朴世堂)'s Interpretation about 『Ulleungdo(鬱陵島)』’ and ‘『Choseon Map(朝鮮圖)』 before Kim Jeong-ho’. This paper aimed to clarify the false insistence by Shimojo Masao. And this paper revealed his inability to interpret Chines character in Park Sae-dang's 『Ulleungdo』 interpretation as well as his false insistence about every records of Choseon concerning ‘Usando’ is not all of ‘Dokdo’ but ‘Jukso(竹嶼)’ that is ‘Takeshima’. This kind of false interpretation stems from the negation of originality of Korean historical view on Dokdo. Also, Shimojo Masao insisted a theory which 'Usando' at the right position of ‘Ulleungdo’ in 『Chseon Map』 which was preserved in Nakanoshima library established by Osaka prefecture showing 'Usando' located between Gangwondo province and Ulleungdo at the right side of the map was descended from the tradition of 「Paldochongdo(八道總圖)」 of 『Shinzeung- dongkuk-yeoziseungram(新增東國輿地勝覽)』. But this insistence was planned to ignore the amended location of the island in the map after 「Paldochongdo』. In this, we can recognize Shimojo Masao's Dokdo research have a bias for the historical fact at his will and distort the reality. Naturally, Japanese government's false insistence on Dokdo based on Shimojo's theory should be abandoned and again, we clarify the fact in the paper.