An all-solid-state lithium secondary battery includes a positive electrode; a negative electrode; and a solid electrolyte arranged between the positive and negative electrodes, to conduct lithium ions. In the all-solid-state lithium secondary battery, a mixed layer is in close contact with a surface of the solid electrolyte adjacent to the positive electrode, the mixed layer containing the positive-electrode active material and (Lix(1−α), Mxα/β)γ+(B1−y, Ay)z+O2−δ (wherein in the formula, M and A each represent at least one or more elements selected from C, Al, Si, Ga, Ge, In, and Sn, α satisfies 0≤α