In analyzing electronic circuits, it is usually necessary to solve a sparse coefficient matrix comprised of simultaneous linear equations. In order to treat these problems effectively, we have developed a dedicated parallel machine called (sm)2-II (’the Sparse Matrix Solving Machine’ version II). (sm)2-II is composed of multiple clusters, each consisting of multiple PUs (Processing Units) connected by a special communication mechanism called RSM (Receiver Selectable Multicast). Here, we propose an adaptive cluster structure and evaluate its performance. The characteristics of typical problems are analyzed at the beginning of computation. Then the size of each cluster and the connections between clusters are adapted to the problem automatically. Using this mechanism, effective computation is possible in various types of problems.