The problem of the present invention is to provide a sulfide solid electrolyte material with favorable reduction resistance. The present invention solves the problem by providing a sulfide solid electrolyte material having a peak at a position of 2θ=30.26°±1.00° in X-ray diffraction measurement using a CuKα ray, and having a composition of Li(4−x−4y)Si(1−x+y)P(x)S(4−2a−z)O(2a+z) (a=1−x+y, 0.65≤x≤0.75, −0.025≤y≤0.1, −0.2≤z≤0).