In this paper we have studied effects of motorway improvement in Japan. In this study we used a computable general equilibrium model which have been proposed for impact studies of regional policies. By using this operational model based on micro economic theory, we are able to study impacts not only the changes of demand and supply, but also the change of price, income, utility and so on. Through this study, the following things have been appeard. Though motorway network was constructed rapidly, it is appeared that in delayed case of motorway construction industries such a electric machinery didn't located in rural area. Moreover, in early step of motorway construction, its benefits were imputed to a few regions where motorway had been constructed, but as motorways had been constructed more and more, the benefits were spread to all regions.