Morphological differentiation and geographic distribution of the maruta and jusan-ugui types of anadromous cyprinid Tribolodon brandtii were investigated based on 208 individuals from 22 localities scattered through the whole distribution range of the species from Japan, Korea to Russia. Significant difference at less than 5 ％ level became clear in six counting and 11 measuring characteristics between the two types. Principal component analysis（PCA）and canonical discriminant analysis（CDA）also supported their morphological difference. Their distribution ranges were parapatricaly separated, pacific coast of the Honshu Island from the Tama River, Kanagawa Prefecture, to Ohunato Bay, Iwate Prefecture, Japan, for the maruta type, and the other regions from the Oirase River, Aomori Prefecture, to the Koyabe River, Toyama Prefecture of the Honshu Island and around the Hokkaido Island, Japan, the Sakhalin Island and Primorie, Russia, and Korea for the jusan-ugui type. The data strongly suggest their differentiation at more than subspecific level.