In Japan, regarding citizen participation, it is expected that children’s activities in a public space would encourage adults to participate in community development. However, Japanese cities today are not open as playgrounds for children. To create a children’s playground more lightly and quickly, we organize a pop-up children’s playground in a public space and observe the participants. Through this experiment, we found that even pop-up and simple methods can elicit active play among children in today’s public space. Also, when the management and rules are clear, it has been found that even what might be considered a nuisance in a public space, adults take it as a good experience for children. Furthermore, it has the potential to encourage adults to participate in community development when the pop-up playground is suitable for the public space and has a sustainable and reproducible planning and management method. It may not immediately lead to specific activities or participation, if more adults accept children’s play in public spaces in a positive way through pop-up playgrounds, we may be able to soften the decisions and attitudes that push children out of cities