Renovation project for a wooden house in an old residential area in Neyagawa City. The 40-year-old Japanese house was found to have deteriorated water circulation areas, no heat insulation, and damaged structural members. On the other hand, the interior design of the house and garden, as well as the household goods remaining in the house, indicated that the previous occupants had lived in the house with a lot of love and care. In order to efficiently improve the living environment within a limited budget, we reinforced the insulation from the inside, mainly in the living area, and conducted well-balanced seismic retrofitting throughout. In addition to performance improvements, we also considered restoring the house's Japanese-style appearance while adapting it to the client's lifestyle. The heavily damaged water area and the Japanese-style room on the north side of the house were combined into the LDK to reorganize the living space. Shoji screens were installed in the openings, and expressive natural materials such as sand plaster, chestnut wood, and Tatsuyama-stone catch the stable natural light on the north side and give soft shadows to the space. In contrast, the Western-style room located on the southwest side was planned to be a bedroom with white as its base color, and the entire room was designed to be a bright, veranda-like place. The Japanese-style room, which was only repaired, was replaced with a down-lighting system with reduced illumination, so that the natural light through the shoji paper sliding door would be more beautiful. By taking into consideration the light and materials used in each room, we aimed to restore the appearance of the existing Japanese house as a new living space with a sense of comfort.