The present invention provides a sheet-shaped polymer secondary battery of layer built type which is a laminate of plurality of sheet-shaped unit cells each of which comprising the following elements (a) to (c):(a) a positive electrode made of a film-shaped polymer having conjugated double bonds and provided with a thin metal layer at one side of the surface of the film and capable of reversibly doping and undoping negative ions,(b) a negative electrode made of a film-shaped polymer having conjugated double bonds and provided with a thin metal layer at one side of the surface of the film and capable of reversibly doping and undoping positive ions, and(c) an insulating porous separator supporting a dopant-containing electrolyte and existing between the positive electrode and the negative electrode.By the use of the sheet-shaped polymer secondary battery of layer built type according to the present invention, the current-collecting efficiency can be enhanced and also the charging-discharging efficiency can be increased.