This is the third article- “Inquiry in the origin of the theory of family, ” in the Japanese Sociological Review. No.6, 1951 and “The background of origin of the theory of family. ” in Memoirs of the Faculty of Liberal Arts & Education of Yamanashi Univ., No. 6, 1955 (both in Japanese) -which was written to criticize the well acknowledged theory which sets the origin of the theory of family in 1861.(I) In this article, I will begin with the problem about the origin of the theory itself. This was the theory which set the origin of the theory of family in Bachofen's Das Mutterrecht. written in 1861, though afterwards Marinowski and others complimented it by Maine's Ancient Law. of 1861. It is generally thought that Engels was the first advocater to set Bachofen's Das Mutterrecht, as its origin in the Vorwort of his Der Ursprung der Familie, des Privateigentums und des Slaats. IV Aufl. (1891). But, it is noteworthy that the previous year 1890, there had been published a book, Tableau des origines et de l'revolution de la familie et de la propriete by Kovalevsky, the first chapter of which was very similar to that of Engels. Both assert decisively that there was not any theory of family but arguments under the influence of Pentateuch which they both affirm as “verbiage” or “nicht die Rede sein”. Both of them coincidently take their origin in Bachofen's theory, though Kovalevsky esteems the study of the primitive peoples which has survived by MacLennan's Primitive Marriage. 1865 along with the historical study of Bachofen. It seems to me doubtful that Engels formed his theory of the origin in 1861 only by himself, because Engels made a few supplements in his IV Aufl. referring them to this book of Kovalevsky.(II) I begin the problem by quoting Russell who say, “ The period of history which is commonly called” modern “has mental outlook which differs from that of the medieval period in many ways. Of these, two are the most important : the diminishing authority of the Church, and the increasing authority of science. ” “ The rejection of ecclesiastical authority which is the negative characteristic of the modern age, begins earlier than the positive charactristic, which is the acceptance of scientific authority. ” “ The first serious irruption of science was the publication of the Copernican theory in 1543 ”(History of western philosophy. 1946. p. 511-2). If so there is some probability of finding arguments on the family without bearing the Pentateuchal stamp very early.Of Trattato della famiglia. by L. B. Alberti (1404-72), W. Sombart (Der Bourgeois. 1913) and Y. Kaneko (Kindai-Humanism to Rinri. 1942) speak in high estimation of its modernistic character, in spite of the fact that M. Weber (Protestantische Ethik und der Geist des Kapitalismus. 1920) shows sceptism of it. Weber conceives that Alberti in stating the economy of family detached economics from religion, and by so doing he had influences upon “die Entwicklung der modernen Wirtschaftslehre (und auch : des modernen Wirtschaftspolitik)”.