In this work, the synthesis of a strong acid ion-exchange resin with a monolithic microhoneycomb structure was attempted using the ice templating method, a new micromolding technique developed by the authors. The obtained monoliths were found to have micrometer-sized straight channels, and the thickness of the walls which form the channels were also in the micrometer range. Through titration experiments, it was confirmed that the monoliths have a sufficient ion exchange capacity and strong acidity. The monoliths also showed catalysis in esterification reactions which indicates that they can be used as an effective solid acid catalyst with an extremely low hydraulic resistance in various commercial reactions.