As well as anions and ion exchange of interest, crystals excellent hydrotalcite-like materials and methods of manufacturing the same small and basal spacing is large anion exchange performance, as well as method of immobilizing harmful substances. After synthesizing the hydrotalcite-like material by mixing an alkaline solution comprising an acidic solution and an alkaline containing aluminum ions and magnesium ions to produce a hydrotalcite-like material was removed or neutralized water without aging . The molar ratio of the aluminum ions and magnesium ions is 1: 5 to 1: is preferably in the 2 range. The hydrotalcite-like material is added or added so as to be synthesized directly target position to the target as well slurry to be added to the subject in the powder after synthesis, it is possible to immobilize the hazardous substances, this anion adsorption by the filter containing the hydrotalcite-like substance is also possible.