The purpose of this paper is to find out the set of the factors influencing on the successful voluntary consolidation among local governments. This paper considers the voluntary consolidation as a kind of coordination mechanism and institutional collective action process between local governments, and identifies the configurations of the causal factors influencing the voluntary consolidations by applying the fuzzy-set analysis. It is found that the sets of the causal factors which include political and economic homogeneity factors in the region, and interlocal political, economic, and social homogeneity factors, and prior consolidation experience between regions have positive effects on the consolidations. Also, it turns out that interlocal homogeneity and conformity between regions should be considered significantly for institutionalization which supports the consolidation between local entities.