Electric power is supplied from a fuel cell to a portable personal computer (210) having a heat-producing section (212) which generates heat during operation. The fuel cell includes electrolyte, a fuel electrode and an oxidant electrode arranged to sandwich the electrolyte, and a fuel supply section capable of supplying fuel which has absorbed heat of the heat-producing section (212) to the fuel electrode. The fuel supply section removes the heat from the heat-producing section (212) by supplying fuel to the fuel electrode when the fuel is heated by heat exchange. Thus, it is possible to improve the battery efficiency of the fuel cell and suppress increase of the temperature of the heat-producing section.