The purpose of this study is providing useful information for consumer-friendly house plan by investigating remodeling apartments according to the area type and size. In order to achieve this aim, case study was applied. The case study was conducted of five small, medium, and large size apartments through depth-interviews, actual survey, and questionnaires on the remodeling behavior, interior design, and interior atmosphere. The results of the study are as follows: Structural alterations were frequent in communal area, and then in private and household areas. Changing lighting fixtures was frequent in all area types, and especially, in communal areas installing extra decoration was frequently observed. Besides, alterations of doors and window frames were carried out in communal, private, housework and service areas by using wood, aluminum sashes, double-glazing, and paint coating. Finally, in housework areas the material and color of counters were changed into wooden and achromatic.