It may be insufficient to study the derivation of place-names perfectly, especially to find its racial origin through the method of phonetic analysis or by the dray of calling the actual places. It is the most important to catch the features of its distribution finding some grouper about objective place-names in adition to the above mentioned several ways. The distribution feature, so the author says here, denotes the genetic structure concentering round the higher cultural region of one nation. The auther likes to call it briefly with the word of “Pattern” of place-names distribution. Finding out of this pattern we can see the order of its development and the linguistic traps-formations with the knowledge by what nation the place-names were given. This method of place-names study might comes to the important works for the “TOPONOM.c GEOGRAPHY” that will be settled definitely as a new section of science in the nearer future. The author studied by this way the Ainu place-names that they were said so undefinitely, and distinguished the Ainu place-names from the faulse Ainu ones. Fig. 1 The distribution of Ainu place-names, -nai, that means the river or swamp. We find the distribution center of these place-names in Iokkaido, so we can define them as the Ainu place-names. These are scattered also in the northern part of Honsyu and its discontinuous line lies near Sendai city. It seems to had deen the clipnatical northern limit line of rice culture and sericulture, therefore had been suspended the reclamation of the Yamato Dinasty. Fig. 2 This map denotes the distribution of the place-names in which have any phones of pa, pi, pu, pe or po. These phones are very characteristic faeture in Ainu. The discontinuous line of these place-names is found in the Tugaru Str. Fig. 3 The distribution of “Nita”, “Nuta” (each denotes marsh land). These plane-names were very uncertain whether Ainu or old-Japanese, but it is very clear to belong to Japanese from its pattern. Fig. 4 The place-names of Iburi, Eburi, and etc. These were also manifested by its pattern to be the Japanese place-names.