Fusion power reactor studies conducted in Japan are reviewed and their potential merits and R&D issues are listed. Beginning with a tokamak power reactor study carried out in 1973, there have been a considerable number of studies for both magnetic and inertial confinement fusion schemes. It is of interest to note that there are at least one power reactor concept for each major confinement scheme studied in Japan. Most of them are for the D-T fuel cycle but in recent years D-3He fuel reactors have come to be studied.