For global environment to be preserved, existing underground structure must be reused actively, because domolishment of it demands enormous energy compared with that of above ground. This paper shows a rebuilding project of 38-year-old building in which new structure was rebuilt on the reused basement. In reusing underground structure, much attention was paid to balance of architectural planning and structural planning, structural continuance in the connection floor, safety of rebuilt building which had much floors than the original one and quality control of reused structure in construction. As a result, effective reduction in construction cost and environmental impact was achieved.
