Lithium primary battery

A lithium primary battery, comprising:

• a wound electrode group, and a nonaqueous electrolyte solution, wherein
• the electrode group is constituted by spirally winding a belt-shaped positive electrode, a belt-shaped negative electrode, and a separator disposed between the positive electrode and the negative electrode,
• the positive electrode contains at least one selected from the group consisting of manganese dioxide and graphite fluoride,
• the negative electrode includes a lithium alloy,
• the lithium alloy is one or more selected from the group consisting of magnesium and aluminum, and contains at least the magnesium,
• a total content of the magnesium and the aluminum in the lithium alloy is 0.02 mass % or more and 11 mass % or less,
• the negative electrode has an outermost peripheral region arranged at an outermost layer of the electrode group, and a main region on a more inner peripheral side than the outermost peripheral region, and
• a ratio T1/T2 of a thickness T1 of the outermost peripheral region to a thickness T2 of the main region is more than 0.5 and less than 1.