The purpose of this study is to predict remodeling timing of Permanent Rental Housing through historic data and cash flow analysis. For this aim, the study has estimated cash flow of Permanent Rental Housing considering initial construction costs, government supporting fund, rental incomes and maintenance expenses. Based on the expected cash flow analysis, reasonable remodeling timing is predicted for Permanent Rental Housing. The results of this study are as follows: (1) it is analyzed that building a8e of about 27 years is the best time for remodeling because cumulative surplus amounts reach maximum level, (2) it is required that remodeling should be made before 34 years of age roughly because cumulative surplus amounts change into minus from this time.