A secondary battery includes an electrode assembly including current collecting sections, an electrode terminal, and an adapter sheet connecting the current collecting sections to the electrode terminal. The electrode assembly includes active material layer(s), current collector(s) each including an insulating layer and first and second conductive layers sandwiching the insulating layer, and conductive structures each including first and second conductive members. A portion of the first conductive member extending beyond the second conductive member forms a current collecting section. The current collecting sections are laminated with each other, with one of the current collecting sections directly contacting the adapter sheet. Neighboring ones of the current collecting sections directly contact each other, without any second conductive member arranged therebetween.