A new species of naticid snail is described from Okinawa Island, East China Sea : Naticarius pumilus n. sp. It is the smallest species found so far in the family Naticidae and has a multisulcate operculum, the outermost spiral rib of which is bevelled and has tile-shaped projections. This species is morphologically different from all of its congeners by shell size, shell color pattern and sculpture of operculum.