Recently, Information Technology (IT) has spread quickly in Japan. In this study, we developed a model to estimate the influence of IT on industrial economy and to estimate the related environmental load. This model consists of two modules, input-output analysis module and energy conversion module. The former module estimates multiplied effects of adoption of IT on industry economy, and the latter module calculates CO₂ emission by using the relationship between the emission and industrial production. An IT spreading scenario including evolution of broadband network, electronic commerce (BtoB and BtoC), and telework was considered. As a result of our estimation, demand for power sector increased, and CO₂ emitted from oil products decreased due to reduction of transportation. Total CO₂ emission increased because of large amounts of demands for the power sector.