Tokyo Metropolitan garden of Kyu-Iwasaki-tei garden (former Iwasaki's residence in Taito Ward, Tokyo), constructed by Hisaya Iwasaki the third president of Mitsubishi Group,is today known as one of finest examples of gardens of Meiji period. This paper examines the initial spatial composition of the garden during Hisaya's ownership (1885-1945) and the original design of Shiba-niwa (lawn garden), which has been a decisive characteristic of the garden, under a restorative approach based on interview to Hisaya's bereaved family, examination of existing drawings and old photographs, and comparative study with the other Meiji Era gardens.The examination clarifies that the garden was chiefly comprised of four areas; the lawn garden, the Shoin (Japanese style house) garden, the approach and rotary, and the flower garden. Particularly, this study notices significant characteristics of the lawn garden that deserve to title this garden a standard model of Meiji Era gardens in Tokyo. The result also indicates that the site itself formerly formed Japanese and Western landscape axes, corresponding to the coupling of Japanese and European style houses.