An exemplary all-solid lithium secondary battery includes a positive electrode including a positive-electrode active substance layer, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode. The positive-electrode active substance layer is composed of lithium cobaltate, and has an α-NaFeO2 type crystal structure. The positive-electrode active substance layer has a (018) plane oriented in a normal direction of a principal face of the positive-electrode active substance layer. The solid electrolyte layer is composed of lithium lanthanum titanate and has a tetragonal perovskite-type crystal structure. The solid electrolyte layer has a (110) plane or a (102) plane oriented in a normal direction of a principal face of the solid electrolyte layer.