Solid electrolyte composition, method for producing same, storage method and kit, solid electrolyte-containing sheet, storage method and kit therefor, and all-solid secondary battery

Provided are: a solid electrolyte composition, which contains a sulfide-based solid electrolyte having a conductivity of ions of a metal belonging to Group 1 or Group 2 of the periodic table, a binder, and a dispersion medium, wherein an amount of oxygen dissolved in the solid electrolyte composition is 20 ppm or less; a method for producing the same; a storage method and a kit; a solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition; a storage method and a kit therefor; and an all-solid secondary battery.