In 1882, he took part in the investigations on the European constitutions, and after he came back, he was involved in making drafts of the Constitution of the Empire of Japan as secretary to ITO, along with Kowashi INOUE and Kentaro KANEKO.
1882年（明治15年）に欧州憲法調査に随行、帰国後伊藤の秘書官として井上毅、金子堅太郎と共に大日本帝国憲法起草に参画。