Provided is a nonaqueous electrolyte secondary battery including a bottomed cylindrical positive electrode casing and a negative electrode casing which is fixed to an opening of the positive electrode casing through a gasket. The opening of the positive electrode casing is caulked to the negative electrode casing side to seal the accommodation space. A diameter d is in a range of 6.6 mm to 7.0 mm, and a height h1 is in a range of 1.9 mm to 2.3 mm. A shortest distance L1 between a caulking tip end and the negative electrode casing in the opening of the positive electrode casing is equal to or less than 110% of an average sheet thickness of the positive electrode casing, a shortest distance L2 between a tip end of the negative electrode casing and the positive electrode casing is equal to or less than 100% of the average sheet thickness of the positive electrode casing, and a distance L3 between the tip end of the negative electrode casing and the bottom of the positive electrode casing is equal to or less than 75% of the average sheet thickness of the positive electrode casing.