A non-aqueous electrolyte primary battery including: a positive electrode including a fluorinated carbon; a negative electrode including a lithium metal; a non-aqueous electrolyte; and a separator, wherein the non-aqueous electrolyte includes a non-aqueous solvent and a solute dissolved therein, the non-aqueous solvent including .gamma.-butyrolactone, and the separator includes a microporous membrane onto which a phosphoric acid ester is provided, the phosphoric acid ester being represented by the formula (1): ##STR00001## where R.sup.1 is an alkyl group, R.sup.2 and R.sup.3 are each independently an alkylene group, and n is an integer.