NOVELTY - Manufacture of crystalline lithium-ion conductive solid electrolyte sheet involves heat-processing and press-molding lithium-ion conductive glass-like solid electrolyte to sheet form. The lithium-ion conductive glass-like solid electrolyte is sulfide-type inorganic solid electrolyte which does not contain lithium hydroxide and is manufactured using raw materials comprising lithium sulfide and phosphorus pentasulfide, lithium sulfide, elemental phosphorus and elemental sulfur, or lithium sulfide, phosphorus pentasulfide, elemental phosphorus, and/or elemental sulfur.    USE - Manufacture of crystalline lithium-ion conductive solid electrolyte sheet is used for forming solid electrolyte layer of solid secondary battery (claimed). Uses include but are not limited to two-wheeled motor vehicle, electric vehicle, hybrid electric vehicle, portable information terminal, portable electronic device, and domestic electric power storage apparatus.    ADVANTAGE - The lithium ion conductive solid electrolyte sheet has excellent ion conductivity.    DETAILED DESCRIPTION - Manufacture of crystalline lithium-ion conductive solid electrolyte sheet involves heat-processing and press-molding lithium-ion conductive glass-like solid electrolyte to sheet form. The lithium-ion conductive glass-like solid electrolyte is sulfide-type inorganic solid electrolyte which does not contain lithium hydroxide and is manufactured using raw materials comprising lithium sulfide and phosphorus pentasulfide, lithium sulfide, elemental phosphorus and elemental sulfur, or lithium sulfide, phosphorus pentasulfide, elemental phosphorus, and/or elemental sulfur. The heat processing temperature is higher than the glass transition point of the sulfide-type inorganic solid electrolyte. An INDEPENDENT CLAIM is included for solid secondary battery (1), which comprises a solid electrolyte layer (20) containing lithium-ion conductive solid electrolyte sheet, clamped between the positive electrode (10) and negative electrode (30), the positive electrode and negative electrode.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of solid secondary battery. (Drawing includes non-English language text)    Solid secondary battery (1)    Positive electrode (10)    Solid electrolyte layer (20)    Negative electrode (30)    Electrical power collector (40, 42)