The paper described the fiscal 1997 result of the study of scenarios for introducing hydrogen to the urban area. In the case of studying it in London, it was found that hythane (mixture of hydrogen into town gas) was effective, but in the case of doing in Tokyo, it was found that the scenario was undesirable because of the increasing infracost. Accordingly, another scenario was studied. It was assessed from the aspects of environmental advantages, infracosts, and potential advantageous values in urban areas associated with hydrogen utilization (hydrogen premium). It is most effective to use hydrogen as a fuel of transportation means from the aspect of environmental merits as the decrease in external cost. In Tokyo, the dependence upon electric power is large, and therefore it is attractive to introduce highly efficient fuel cells which enable the dispersed cogeneration using hydrogen. The value of hydrogen is determined by the avoidance of environmentally influential substances and the surplus generated output by fuel cells (substitution for the existing natural gas). When the high external cost can be assumed, the value of hydrogen becomes large. The paper also considered the arrangement of infrastructures in Tokyo. 187 refs., 14 figs., 18 tabs.