This study aims to clarify the regional characteristics of heat balance in an urban space of a city. Since most of major cities in Japan are located at coastal areas, special attention is paid to the contribution of sea breeze to the heat balance in urban area in this study. The spatial distribution of heat budget inside Sendai is drawn, as "heat balance map ". This map shows the area where the influence of sea breeze is larger than those of heat generated from ground surface and artificial heat release. In this area, it is effective to introduce sea breeze into urban areas for reducing the air temperature by matching the building arrangement with wind conditions.