Zirconia-cluster/saponite composites were prepared and evaluated as solid acid catalysts. The saponite layer was destructed in the composite through the dissolution of Al ion. The amount of zirconia-cluster in the composites was positively correlated with the Al amount, suggesting that zirconia-cluster inhibits the Al dissolution. Both the amounts of Bronsted and Lewis acids were increased by combining zirconia-cluster to saponite. Results show that Lewis acid on the saponite surface plays an important role on the entire catalytic activity on isomerization of 1-butene. The zirconia-cluster/saponite catalysts provided higher activity with a longer lifetime on this reaction than a commercial montmorillonite-based catalyst. (C)2013 The Ceramic Society of Japan. All rights reserved.