The present invention is to provide a method for producing such a sulfide solid electrolyte that it has high lithium ion conductivity and the total amount of heat generated by the reaction with the charged anode material that proceeds at around 315° C., is reduced. Disclosed is a method for producing a sulfide solid electrolyte, wherein the method includes: a first step of preparing Li3PS4 having a γ structure, and a second step in which a second step mixture that contains the Li3PS4 having the γ structure obtained in the first step and LiX (where X is halogen) is non-crystallized, and the non-crystallized second step mixture is heated in a temperature range of more than 150° C. and less than 190° C.