We introduce a new granulation method for Prussian blue (PB) based on thin-film polymer gel coating. PB particles were strongly supported on a hydrophilic polymer gel porous carrier. Scanning electron microscope (SEM) images confirmed that the PB supported on silica (PBS) samples was thinly covered with the polymer gel containing PB, whereas electron probe microanalysis (EPMA) confirmed that the PB particles mainly existed on the PBS surface. PBS is suitable as a column material for adsorbing low concentrations of Cs.