It becomes difficult to correspond to the urban problem in the system under the economy stagnation. Also present is the continuing low economy growth and a deflation tendency. Therefore, in the income and expenditure system, depending on extra floor sale for the most parts of the income makes the project itself increasingly more risky. In the study, we pay attention to the original feature of the urban renewal development such as right conversion, or the extra floor sale. Theoretically we make clear the decision-making process concerning the extra floor sale. Also, by using the data of the land price, we explain the relationship between the floor demand and the possibility of project execution.