A sulfide solid electrolyte containing lithium, phosphorus, sulfur; and one or more of elements X selected from the group consisting of halogen elements and chalcogen elements excluding sulfur, wherein the sulfide solid electrolyte includes an argyrodite-type crystal structure, and wherein a molar ratio of the lithium to the phosphorus, a (Li/P), a molar ratio of the sulfur to the phosphorus, b (S/P), and a molar ratio of the element X to the phosphorus, c (X/P), satisfy formulas (1) to (3): 5.0≤a≤7.1 (1) 1.0 0 and c>0 are satisfied.