This paper aims to clarify the following from the viewpoint of agriculture and trend toward farm households earning income from other jol 〕s , 1)The formation factors of three − generation households , 2) Difference of changes in households composition for the elderly by difference of the factors . The conclusions are as follows . 1. The formation factors of three − generation households are farm households earning income fro皿 other jobs , urbanization , degree of secondary /tertiary industry , rice croP , 2. Trend to changes in households composition for the elderly are not different . However , changes in number of aged − couple households and aged − single − persons are different by difference of the factors . − ervvrds ' Municipalities . Uouse 加 1ゴ for th θ θ lderly. ThiLee − generation 加 useholds . Agricu /ture. FSIW househo / ds θarning ゴncome from other jobs