Confluent AGMK cells were infected by large plaque SV40 virus. Levels of DNA polymeras $({alpha};and;{eta})$ were measured in the cytoplasm and the cell nucleus. The activities of DNA $polymerase-{alpha}$ which found in both the cell nucleus and the cytoplasm were increased approximately eight folds at 48 hours after infection of SV40 virus. Only insignificant but constant amounts of DNA $polymerase-{eta}$ were found either in the nucleus of the SV40 infected cell or of the uninfected cell. The characteristics of the SV40 virus induced DNA polymerases were compared with that of the uninfected cellular DNA polymerase in regard of the effects of pH, salt concentration, NEM concentration and temperature on those enzyme activities. No differential effect was found between both enzymes. Endouclease activities wre examined in the purified DNA $polymerase-{alpha};and;{eta}$. The low level of endonuclease activity which might cut SV40 DNA 1 at one site was observed in the DNA $polymerase-{alpha}$ whereas high but nonspecific endonuclease activities were found in the DNA $polymerase-{eta}$.