SOLID ELECTROLYTE COMPOSITION, SOLID ELECTROLYTE-CONTAINING SHEET, ALL-SOLID STATE SECONDARY BATTERY, AND METHOD FOR MANUFACTURING SOLID ELECTROLYTE-CONTAINING SHEET AND ALL-SOLID STATE SECONDARY BATTERY

Provided are a solid electrolyte composition containing a polymer (A) having a mass average molecular weight of 5,000 or more, a compound (B) having two or more polymerization reactive groups and having a ratio of a molecular weight to the number of the polymerization reactive groups (molecular weight/the number of the polymerization reactive groups) being 230 or less, and an electrolyte salt (C) having an ion of a metal belonging to Group I or II of the periodic table, in which a mass proportion of the compound (B) occupying in a component having a boiling point of 210° C. or higher, which the solid electrolyte composition contains, is 10% or more, a solid electrolyte-containing sheet and an all-solid state secondary battery that are obtained using the solid electrolyte composition, and methods for manufacturing a solid electrolyte-containing sheet and an all-solid state secondary battery.