We investigated the formose reaction using a zeolite impregnated with thiazolium catalyst. The zeolite catalyzed the formose reaction in an organic solvent and then the reaction rate was pseudo first order with respect to the formaldehyde concentration. The main products were DHA, erythrulose, and 4-hydroxymethyl-2-pentulose. The selectivity of the branched sugar was increased by the choice of conditions. For the reuse of the catalytic zeolite, washing with water was one of the important factors. These results are important for sugar synthesis processes from formaldehyde in one step.