A new slug of the family Philiomycidae, Granulilimax fuscicornis, is described on the specimens found in Shikoku as a new genus and species. This new slug is extremely small-sized and is distinguished from the related species, Meghimatium bilineatum (Benson, 1842) by a minute granule, longitudinal band like elliptical circle on the body and the structure of genitalia.