Desulfurization efficiency and reactivity of the coal on which Ca^<+2> was loaded by using the principle of electric double layer was estimated and it was compared with technics of loading Ca^<2+> to the coal generally done. the amount of Ca^<+2> loading by EDL adsorption was 2-3 times as much as that by a conventional method. Furthermore the higher amount of Ca^<2+> loading could be obtained by varying the conductive of electrolysis and electrolyte. its combustion reactivity increased by several percent.