This study aims to clarify the effect of the spatial formation of naga-hisashi, the long eaves that cover Okura's entrances in Japanese Okura-syo (the premises of storehouse which stored the rice) of the Edo period. And the regional characteristics in Japan are shown. Naga-hisashi connected multiple doorways in front of the Okura, and were prominent in the Okura-syo of western Japanese domains and the Shogunate. Not limited to the original function of eaves, these naga-hisashi were also used as inspection stations (enclosure type) or formed corridors (open type), thereby making the Okura-syo more functional.