<p> In recent years, "welfare conversion" is attracting attention. It means to renovate and utilize existing buildings as useful local stocks for welfare functions and services. It is thought that the use and composition of the rooms have changed before and after, but the actual conditions have not been clarified. The purpose of this paper is to analyze the change of the room composition before and after the conversion from another type buildings in Nagano City.</p><p> </p><p> First, as a preliminary survey, we extracted 79 converted welfare facilities from 446 facilities in Nagano City. After that, we did a detailed survey at 49 facilities and analyzed them in three stages : before conversion, how to convert, after conversion. There was no major tendency in the room composition before conversion. As for the method of conversion, room division and integration were often seen, and we realized that the largest rooms, which are relatively large in the whole, were often room division. In addition, it was confirmed that complex conversion was done with room additional. Furthermore, we analyzed the room composition after conversion based on the correspondence between functional training rooms and private rooms which are important rooms in welfare facilities, and group of rooms or the largest room. We understand that group of private rooms and the largest functional training room occupy most of the room composition, and it is important to make largest functional training room after conversion.</p><p> </p><p> Next, we compared the room composition before and after conversion, and found five types of units that had common room composition changes. As a result, we found that not only the before room composition was converted to welfare facility just as it is, but also the expansion and renovation was performed. Furthermore, according to the flow of conversion, the functional training rooms will be made regardless of the existing condition, so various functional training rooms will be provided regardless of the facility classification. For this reason, it is necessary to anticipate spatial issues such as livability.</p><p> </p><p> Thus, we clarified that the changes in the room composition of the existing facilities were converted while taking advantage of the characteristics of the before room composition, and made a private room and a function training room. In addition, we think that it is necessary to discuss about the livability required for not only the private room but also the functional training room in the future welfare conversion.</p>