The solid electrolyte material of the present disclosure is a solid electrolyte material made of Li, Ca, Y, Gd, X, and O, where X is at least one selected from the group consisting of F, Cl, Br, and I; the molar ratio of O to the sum of Y and Gd in the entire solid electrolyte material is greater than 0 and 0.42 or less; and O is present in a surface region of the solid electrolyte material.