Abstract: A main object of the present disclosure is to provide a sulfide solid electrolyte with high ion conductivity. The present disclosure achieves the object by providing a sulfide solid electrolyte including a LGPS-type crystal phase containing a Li element, an M element, a P element, and a S element, wherein: the M element is at least one kind or more of an element selected from Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb; and in a 31P-NMR measurement, when y (ppm) designates a half value width of a peak having an apex at a position of 77 ppm±1 ppm, and x (%) designates a rate of impurity phase measured, the sulfide solid electrolyte satisfies a below formula (1): y??0.0431x+4.28??(1).