While the society becomes older, the quality growth on the service adequate to seniors is required. The service design is highlighted as a measure to improve the quality of service. And actually, success cases through the service design in various areas are globally introduced. In this study, a research is conducted to develop a service scenario to expand seniors' communication by applying the service design methodology. To analyze seniors' behaviors related to the communication, profiles are established by performing interviews with professionals and the qualitative survey to seniors. And based on the profiles, an idea workshop is conducted with multi-disciplinary experts to develop ideas for seniors' communication. The representative service is drawn by refining ideas. And the detailed service scenario and the video prototype are developed by concentrating one service scenario. The developed service scenario is anticipated to be utilized as a base material to develop services to expand seniors' communication in the future.