By the "roller tube" technic, the author tried the tissue cultivation of the virus of infectious hepatitis. The hepatitis virus isolated by Murakami et al. from hepatitis patients with the embryonated hen's egg or mouse was used throughout this work. The result were as follows: 1) The inoculation of the virus into the medium composed of fragments of skin or muscle of the chick embryo, or suckling mouse did not produce any cytopathogenic effect. The inoculation of each generation of the serial cultivation into the mouse, however, produced the typical pathological changes; this might be taken as the evidence that the multiplication of virus occurred, at least to some extent, in tissue cultures. 2) Judged from the pathological changes in the mouse inoculated with the emulsion of virus infected tissue fragments, the multiplication of virus appeared to be worse in the medium of liver fragments than in that of skin or muscle. 3) When used as the antigen for infection protecting test, the inactivated emulsion of the tissue cultures of virus was less effective than that of the chick embryo by Murakami et al.; this might be the evidence that a high degree of virus multiplication could not be obtained by the tissue cultivation. However, the fact that some degree of infection protective power was obtained by the inoculation of tissue cultures of virus, suggested the possibility of practical application of tissue cultures of hepatitis virus to the vaccination.