PURPOSE: To prevent a drop in the characteristics of a battery due to the volatilization of a component by dividing space between a flat positive electrode current detector and a flat negative electrode current collector faced to each other with an insulator, and also keeping each divided space in slightly decompressed state.

CONSTITUTION: A negative electrode active material 16 is laid on a negative electrode current collector 14. Thereafter, a polymeric solid electrolyte as a separator 17 is screen printed on the material 16 and cured. Also, a positive electrode active material 18 is printed on the separator 17 and cured. Then, an insulator 20 having grid-like holes is thermally bonded to the internal surface of a positive electrode current collector 12 with a heating roll at temperature approximately between 150 and 190°C, in such a way as not to generate bubbles at a bonded boundary. Also, the collector 12 is superposed on the other collector 14, and the insulator 20 is bonded to the surface the collector 14, while being passed between rolls heated up to approximately 180°C. In this case, the temperature of gas residual in a battery at a bonding process rises and is kept in expanded state. Thus, decompressed state is generated, when the temperature drops. According to this construction, productivity can be enhanced.