In this study the energy consumption and the CO_2 emissions of housing in prefectural capitals all over Japan have been estimated and characteristics of the transition of them in recent 30 years have been made clear. The energy consumption was increasing remarkably in every cities, and this increase was influenced by climate, expenditure, and residential area. To reduce the v emissions 6% below 1990 levels, 20% of 1995 levels must be reduced in average. In many cities, the major factor of the increase of CO_2 emissions was the increase of using lighting and electrical outlet.
