When transferring an adhesion layer 28 to an electrode layer 12a, carrier sheets 20 and 26 are fed between first and second transfer rolls 40 and 42 so that a rear surface of a first carrier sheet 20, in which the electrode layer is formed, makes contact with a first transfer roll 40 and a rear surface of a second carrier sheet 26, in which adhesion layer 28 is formed, makes contact with a second transfer roll 42; and a first transfer roll 40 is heated at a first predetermined temperature T1 (° C.), a second transfer roll 42 is heated at a second predetermined temperature T2 (° C.), in which a first predetermined temperature T1 and a second predetermined temperature T2 satisfy 60