1. A clustering apparatus of probabilistic graphs, comprising: a center selection processor configured to select one or more centers among the probabilistic graphs; a center determination processor configured to calculate a minimum bound and a maximum bound of a distance with respect to each of the centers, for each of the probabilistic graphs, and determine a center, among the centers, to which the probabilistic graphs are to be allocated based on the minimum and maximum bounds; and a clustering processor configured to allocate the probabilistic graphs to the center to generate one or more clusters that are used for data analysis.