Some therapeutic methods of cancer therapy have been developed. Of these, we tried soft-heating hyperthermia. We created a thermosensitive magnetic powder coated with Ag as a heater for cancer therapy. This powder can generate more heat due to losses through hysteresis and inductive current than magnetic powder alone. We could also control the temperature of the heater by using the Curie point. Consequently, we used thermosensitive magnetic powder coated with Ag. This powder composed of Ni-Cu-Zn ferrite granules and Ag was used as the heater for hyperthermia. The Ag coating was achieved by baking Ag paste on the powder. We examined what effect the metallic thickness had in relation to the thermosensitive magnetic powder coated with Ag for cancer therapy. We confirmed that we could increase the heating properties of the powder by selecting the metallic thickness.