After graduating from Tokyo University (1902) Inoue Han became an engineer for Wakamatsu Harbor Constructing Company and then served the Ministry of Finance (1907). Inoue Han became instructor at his alma mater (1916), joined the Ministry of Internal Affairs (1919) which sent him to Europe and America on an inspection trip (1922). Returning home rejoined his alma mater as professor (1924). Most of his work was done in Kobe Harbor and later he helped repair the damage caused by the Great Earthquake (1923) to Yokohama Harbor.