A sulfide solid electrolyte comprising lithium, phosphorus and sulfur, wherein the sulfide solid electrolyte has a diffraction peak A at 2θ=25.2±0.5 deg and a diffraction peak B at 29.7±0.5 deg in powder X-ray diffraction using CuKα rays, an area ratio of a peak derived from PS43− glass to the total area of peaks derived from glass observed in solid 31P-NMR measurement is 90% or more and 100% or less, and an area ratio of peaks derived from glass to the total area of all peaks at 60 to 120 ppm observed in solid 31P-NMR measurement is 1% or more and 45% or less.