Selective dehydration of glucose to anhydroglucoses, 1,6-anhydro-beta-D-glucopyranose (levoglucosan) and 1,6-anhydro-beta-D-glucofuranose, which are highly value-added intermediates for drugs, polymers, and surfactants was performed. Solid acids with sulfonic acid groups like Amberlyst-15 were found to effectively produce anhydroglucoses in polar aprotic solvents.