A solid electrolyte material contains Li, M, and X. M contains Y, and X is at least one selected from the group consisting of Cl, Br, and I. A first converted pattern, which is obtained by converting the X-ray diffraction pattern of the solid electrolyte material to change its horizontal axis from the diffraction angle to q, includes its base peak within the range in which q is 2.109 Å−1 or more and 2.315 Å−1 or less. A second converted pattern, which is obtained by converting the X-ray diffraction pattern to change its horizontal axis from the diffraction angle to q/q0, where q0 is the q corresponding to the base peak in the first converted pattern, includes a peak within each of the range in which q/q0 is 1.28 or more and 1.30 or less and the range in which q/q0 is 1.51 or more and 1.54 or less.