The purpose on this paper is search of design solutions which are excellent in workability by multi-objective optimization of base-isolated reinforced concrete building. This optimal method uses grouping of frame member to search such solutions. Comparing between the ability of searched design solutions and that of the example of execution, the proposed method found the design solutions which have better ability. These solutions had regularity in the arrangement of the member. Consequently, the effectiveness of the optimal method with grouping was demonstrated.
