A method for manufacturing a packed electrode comprises steps of: disposing an electrode between two separation layers made of a resin; disposing a heat-resistant layer between at least one of the two separation layers and the electrode; stacking the two separation layers, the electrode, and the heat-resistant layer; sandwiching, by a pair of sealing chips, an overlapped part of the two separation layers overlapped outside the electrode through the heat-resistant layer and applying pressure and heat thereto; and breaking the heat-resistant layer in the pressured and heated overlapped part and thereby joining the two separation layers. According to the manufacturing method, integrating the heat-resistant layer with the packed electrode makes it possible to reduce the number of stacking steps.