To provide a cap assembly capable of preventing the generation of cracks in an exhaust port, and to provide a secondary battery which is equipped with the cap assembly.

In the cap assembly 30, including a cap plate 31 having an exhaust port 313 on one surface, the cap plate has a reinforced part 314, in a region adjacent to the exhaust port. In a secondary battery 100, including the cap assembly 30, the cap assembly includes the cap plate 31 having the exhaust port 313 on one surface, and the cap plate has the reinforced part 314, in a region adjacent to the exhaust port of a surface on the opposite side to the surface having the exhaust port. Alternatively, in the secondary battery 100, the cap plate 31 has the reinforced part 314 in the region adjacent to the exhaust port on one surface having the exhaust port 313.