A lithium metal secondary battery includes a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte. The positive electrode and the negative electrode are wound to form an electrode group. The positive and negative electrodes face each other with the separator between the positive and negative electrodes. The electrode group has a space for accommodating at least part of the nonaqueous electrolyte when fully discharged. X and Y satisfy 1.00≤X/Y