Crowdfunding is a new funding method through which founders request small amounts of funding from a large number of people through an online platform. Crowdfunding facilitates a new type of social capital and exhibits a unique form of social dynamics, thus attracting the interest of sociologists and other social scientists. Previous studies have focused on social relationships in crowdfunding such as direct reciprocity and consider how they contribute to the success of funding. The social structure of crowdfunding, however, involves more complex social relationships and it may contribute to the success of a new venture or project in many ways. In this study, we focus on a specific type of triadic social structure, the buddy relation, which can be described as a relationship through which project founder x, who previously backed another founder z's project, receives financial backing from the other backers of z's project. We found that the buddy relation occurs significantly more often than randomly, concluding that this structure facilitates the gathering of financial backing and may contribute to the success of a crowdfunded project.