A solid oxide fuel cell includes a metal support cell, in which an anode layer containing nickel, an electrolyte layer and a cathode layer are stacked on a metal support portion. In the method for activating the anode layer in the solid oxide fuel cell, first, an oxygen-containing gas is introduced into the anode layer to oxidize the nickel. Next, a hydrogen-containing gas HG is introduced into the anode layer to reduce the nickel oxide formed by oxidizing the nickel, and to increase conduction paths of the nickel that electrically connect the electrolyte layer to the metal support part in the anode layer.