The establishment of museums with a specialty under governmental or public agencies aims to realize public relations that manifest the preservation and succession of those agencies. Since the 2000s, however, their operation and vitalization have developed at a relatively slower pace compared to their rapid increase in numbers. The major problems of museums with a specialty under the agencies are a lack of curators and or collection, resulting in difficulties in producing new contents. In particular, some of the museums were unable to hold special exhibitions or held them for more than one year. The Court Museum of the Supreme Court has many problems: permanent exhibitions only imitating the general museums, lack of collection and curators, lack of understanding on the works of the museum within the agency, among others. Those museums that are lacking a collection or are vulnerable to holding exhibitions have been presented with fresh opportunities with the advancement of an era of new museums that involves a new awareness on the collection. This study aims to introduce cases in which museums with a specialty found their development plans in participatory exhibitions to be in line with a changing environment for museums. It is the participatory exhibition of the Court Museum of the Supreme Court which was designed by the cooperative project-collaborative development model suggested by Nina Simon among other models. This exhibition broadens the scope of the audience and served as an opportunity to change the previous direction of the museum. The agency came to understand that the operation of the museum centered on the audience, and afterwards, it started to consider the audience rather than the public relations of the agency from the phase of deciding the themes of the special exhibitions. Thus, this study intends to suggest the process of the participatory exhibitions of the Court Museum of the Supreme Court that can be an exemplary case to seek for the appropriate ways to create new contents.