NOVELTY - A solid electrolyte is a particulate solid electrolyte containing solid electrolyte particles. The solid electrolyte particles contain sulfur and lithium, and have average particle size of 1.5 mu m or less. The particle size of 90% or more of solid electrolyte particles is 2.5 mu m or less.    USE - Solid electrolyte is used for forming solid electrolyte film and liquid mixture for positive electrode compound material and negative electrode compound material for lithium cell for apparatus (all claimed). Uses include but are not limited to portable information terminal machine, portable electronic device, domestic electric power storage apparatus, two-wheeled motor vehicle, electric vehicle and hybrid electric vehicle.    ADVANTAGE - The solid electrolyte effectively maintains slurry state when mixed with liquid, has favorable particle size, controlled particle size distribution, and provides solid-electrolyte film having improved ionic conduction efficiency. The gap between solid electrolyte particles is reduced.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) liquid mixture, which contains the solid electrolyte and liquid having low reactivity with the solid electrolyte particles and density which is less than the density of solid electrolyte particles;    (2) solid electrolyte film, which contains solid electrolyte particles;    (3) positive electrode compound material, which is particulate positive electrode compound material containing solid electrolyte particles and positive electrode active material particles;    (4) negative electrode compound material, which is particulate negative electrode compound material containing solid electrolyte particles and negative electrode active material particles;    (5) lithium cell, which consists of positive electrode, solid electrolyte film and negative electrode; and    (6) manufacture of solid electrolyte, which involves wet-grinding the solid electrolyte particles and forming solid electrolyte with predetermined particle size.