In recent years, there has been an increase in the number of cases of extending the life of existing buildings through seismic retrofitting that involves reducing or expanding them. Most of them are seismically reinforced using structures such as steel braces and RC load-bearing walls. In designing architecture, it is necessary to achieve all three of "use, strength, and beauty." In this plan, we propose a method of seismic retrofitting of buildings using seismic reinforcement members that satisfy "use, strength, and beauty" while finding unique value in existing buildings and assigning suitable uses after carefully reading the context of the site.