A sulfide solid electrolyte containing lithium, phosphorus, sulfur, and two or more of elements X selected from halogen elements, where the sulfide solid electrolyte includes an argyrodite-type crystal structure, and 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 the following formula (1): 0.23