In this paper, to evaluate reparability and repairing limit state of seismically damaged RC buildings, prediction models for damage index, which represents reparability of buildings, for estimating repairing cost based on damage both in structural and nonstructural element were proposed. As a result of analytical study on prototype building models, it was shown that the influence of each element on reparability of buildings would depend on the structural characteristics of them. Moreover, an approximated evaluation method of damage index was proposed based on fundamental information such as dimension and damage class of structural members, and its accuracy was discussed.