In this paper I make it my chief aim to recognize the system of dialects in the Aichi Prefecture Area, and to grasp the relations among them. I) In that area, the following ten main patterns of distributions of linguistic phenomena were found out of the linguistic maps which I investigated and made. pattern (1): Ise Coast District is predominant as a unit. pattern (2): no regional differences in Aichi Prefecture are markedly observed. pattern (3): the north part of Owari District is predominant as a unit. pattern (4): Chita-Mikawa District is predominant as a unit. pattern (5): Nishimikawa District is predominant as a unit. pattern (6): Atsumi Peninsula is predominant as a unit. pattern (7): Okumikawa District is predominant as a unit. pattern (8): Chita-Nisliimikawa District is predominant as a unit. pattern (9): Chita Peninsula District is predominant as a unit. pattern (10): Nishimikawa District is predominant :as a unit. These are chief patterns, and a number of lower patterns are recognizable. Each main pattern in a number of maps indicates a dialect as the system of the language, and therefore the list of the patterns recognized above coincides with the system of dialects in that area. II) Comparing the dialects one another, I recognized the relatively ancient linguistic phenomena in the south part of Chita Peninsula, Shinojima, Himakajima, Sakushima, and the south part of Atsumi Peninsula.