an inorganic ion - exchanger supported on a carrier suitable for recovery of useful resources in sea water , removal of impurities from high temperature boiler water in nuclear reactors or industrial boilers , removal of impurities in industrial waste water , etc . is prepared by supporting an active component of inorganic ion exchanger , such as hydrous oxide of metal , for example , titanium , zirconium , etc . on a porous carrier such as alumina , silica , or activated carbon , where a ph of a solution in contact with the active component and the carrier is adjusted so that the active component and the carrier can have zeta potentials of opposite polarities to each other , and an inorganic ion - exchanger having a larger amount of the supported active component and firmly supporting less bleedable active component can be obtained by setting out a supporting condition on the basis of the polarity of zeta potential .