An early Asselian ammonoid fauna comprising nine species belonging to nine genera (Agathiceras, Neoglaphyrites, Somoholites, Shumardites, Vidrioceras, Almites, Eoasianites?, Boesites and Metapronorites) and one indeterminable Adrianitidae is described from the Uyamanoro Formation of the Taishaku Limestone at Miharanoro in the Akiyoshi Belt (late Permian accretionary belt), Southwest Japan. The fauna includes four new species: Shumardites umbilicatus, Vidrioceras ellipticum, Almites hayasakai and Boesites biconcavus. The age of the fauna is determined to be early Asselian based on the fusulinoidean biostratigraphy. In addition to the previously known late Asselian taxa, the number of Taishaku Asselian ammonoid genera is now ten genera. This is the only known Asselian ammonoid fauna from the mid-Panthalassa Ocean. The ammonoid faunal composition of this region, the Mid-Panthalassa Realm, is closely related to those of Paleotethyan (Pamirs and South China), Uralian and American (eastern Panthalassa) realms.