In order to evaluate the reduction effect of electric vehicles (EVs) on various atmospheric environmental loads. we have performed a life-cycle inventory analysis (LCI), including the installation of charging stations and regional, seasonal and temporal difference of the energy mix of electricity generation. For an EV converted from a small gasoline vehicle, a regional LCI analysis was carried out in the following steps: (1) location of the charging stations, (2) modeling of charging characteristics of station users, (3) calculation of temporal life-cycle emission intensities of CO2, NOx and SOx by region, season and day. Assuming that total traveling distance is 100,000 km, the electricity consumption rate is 0.119 kWh/km and the charging/discharging efficiency is 70%, the average life-cycle emission of CO2 for that EV was 3.6 t-C throughout Japan. However, if we took regional difference into account, the emission ranged over 70-160% of the average amount. It was revealed that the regional difference of the primary energy mix significantly affected the emissions of EVs during the operation phase.