Provided is a method for producing a sulfide solid electrolyte having excellent productivity and having a particularly small particle size, including mixing a raw material inclusion containing a lithium atom, a sulfur atom, a phosphorus atom, and a halogen atom to obtain an electrolyte precursor, and heating the electrolyte precursor in the presence of a solvent and a dispersant having 8 or more carbon atoms in a molecule thereof in a sealed pressure resistant vessel.