This paper proposes a new approach for motivating people to participate in achieving a sustainable society. The method is called Micro-Crowdfunding, and encourages people living in urban cities to support and contribute to the sustainability of small common resources, such as public sinks, toilets, shelves, office areas and so on. Micro-Crowdfunding is based on the crowdfunding concept and uses the local currency idea, as tools of the social mechanism, to increase people’s awareness of how they participate in keeping the sustainability of common resources. Our approach aims to maintain the sustainability of common resources with people’s small efforts. In this approach, an organizer introduces a new mission for keeping the sustainability of a resource, and investors fund it. Finally, a performer executes the mission, and completes it with minimal efforts achieving the resource’s sustainability.