TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The first inorganic solid electrolyte comprises: 12-45 mass% of a metal oxide of formula (R2O); 0-75 mass% of silicon dioxide; 0-83 mass% of phosphorus pentoxide; 0-10 mass% of a metal oxide of formula (AO2); and 0-20 mass% of a metal oxide of formula (M2O3). The second inorganic solid electrolyte comprises: 3-20 mass% of a metal oxide of formula (R2O); 0-10 mass% of silicon dioxide; 0-60 mass% of phosphorus pentoxide; 15-35 mass% of a metal oxide of formula (AO2); and 0-60 mass% of a metal oxide of formula (M2O3). The second inorganic solid electrolyte has a crystalline layer of sodium super ion conductor (NASICON)-type, beta -iron sulfate-type, garnet-type, or perovskite-type. The content of the first inorganic solid electrolyte is 0.5-15 (preferably 1-15) mass%. The negative electrode layer comprises the first inorganic solid electrolyte, the second inorganic solid electrolyte, a negative electrode active material, and a conductive additive. The positive electrode layer comprises the first inorganic solid electrolyte, the second inorganic solid electrolyte, a positive electrode active material, and a conductive additive. The first inorganic solid electrolyte is composed of a composition of a glass with a glass transition temperature of 250-650 degrees C. The first inorganic solid electrolyte is lithium phosphate. The positive electrode active material in the positive electrode layer is composed of metal substituted lithium oxide of formula (LiMtO2) and/or (LiMt2O4). The negative electrode active material in the negative electrode layer is composed of lithium titanate and/or titanium dioxide. Preferred Method: The heat treatment step is performed at a temperature higher than glass transition temperature of the first inorganic solid electrolyte. A molding step to mold the raw material composition into a compact with a desired shape is further included, and the compact composed of the raw material composition is heated in the heat treatment step. The raw material composition is shaped in the molding step.R = Li or Na;A = Zr, Ti or Ge;M = B, Al, Bi, La, Y or Sc; andMt = Fe, Ni, Co or Mn. EXAMPLE - Powder (25 mg) of negative electrode layer (comprising titanium dioxide (1.25 g), glass ceramic electrolyte (3 g), lithium phosphate (0.25 g) and acetylene black (0.5 g)) was inserted into a die of diameter 11 mm of a tableting device, then the surface of the powder was lightly compacted and flattened by a rod of diameter 11 mm. A powder (50 mg) of solid electrode layer (comprising glass ceramic electrolyte (3 g) and lithium phosphate (0.25 g)) was inserted, the powder of solid electrode layer was leveled so that the pre-inserted powder of negative electrode layer was not deformed, then the surface was lightly compacted and flattened by a rod of diameter 11 mm. A powder (25 mg) of positive electrode layer (comprising lithium manganese oxide (1.25 g), glass ceramic electrolyte (3 g), lithium phosphate (0.25 g) and acetylene black (0.5 g)) was inserted, the entire powders were leveled so that the pre-inserted powders of negative electrode layer and solid electrode layer were not deformed, then an upper die of diameter 11 mm was mounted. Heating was performed up to 600 degrees C while pressing the die of diameter 11 mm of a tableting device at a pressure of 2 tons by a hydraulic press, followed by releasing the pressure and allowing to cool to room temperature, to obtain a sample of all-solid secondary battery.