A lithium primary battery including: a positive electrode containing a mixed crystalline manganese oxide; a negative electrode containing at least one selected from the group consisting of lithium and a lithium alloy; and a lithium-ion conductive non-aqueous electrolyte. The mixed crystalline manganese oxide contains at least .lamda.-type manganese oxide and .beta.-type manganese oxide, and the .beta.-type manganese oxide has a crystallinity of 300 to 500. The mixed crystalline manganese oxide preferably has a specific surface area of 0.5 to 4 m.sup.2/g. The lithium alloy preferably contains at least aluminum in an amount of 0.2 wt % to 15 wt %.