This study examines the effect on the family farm economy of an agrarian reform and a tax reform. For this purpose, we study five farmers in the Yamagata prefecture for the period 1942 to 1948. Our findings are as follows. First, the fund circulation is sound, largely during the war and post-war periods. Second, the investment and capital required by a tenant farmer are large because of the agrarian reform and the increase in the sale of farm produce. Third, income expenditures are large because of the tax reform.