A secondary battery comprising: a battery electrode assembly in which a positive electrode and a negative electrode are stacked alternately with a separator interposed therebetween, wherein said positive electrode and said negative electrode each have a current collector (3 and 8, respectively) and an active material (2 and 7, respectively) that is applied on the current collector (3 and 8, respectively), each surface of said current collector has a coated portion to which said active material is applied and an uncoated portion to which said active material is not applied, said active material has an inclined portion (2a and 7a, respectively) or stepped portion having a decreasing thickness on at least a part of an outer edge of said coated portion, insulators are arranged to cover boundaries between said coated portion and said uncoated portion of said positive electrode, and one or both of said insulators provided on said current collector of said positive electrode have one end which is located on said inclined surface or on said stepped portion of said active material of said positive electrode and which is opposite to said inclined portion or stepped portion of one or both of said active materials formed on both surfaces of said current collector of said negative electrode, and have other end which is located on said uncoated portion of said positive electrode, wherein a combined total thickness of said insulator, a thickness of said active material of said positive electrode at a portion where said one end of said insulator is located, and a thickness of said active material of said negative electrode at a portion that is opposite to said one end of said insulator is less than a combined total thickness of a flat portion of said active material of said positive electrode and a thickness of said flat portion of said active material of said negative electrode.. a battery electrode assembly in which a positive electrode and a negative electrode are stacked alternately with a separator interposed therebetween, wherein said positive electrode and said negative electrode each have a current collector (3 and 8, respectively) and an active material (2 and 7, respectively) that is applied on the current collector (3 and 8, respectively), each surface of said current collector has a coated portion to which said active material is applied and an uncoated portion to which said active material is not applied, said active material has an inclined portion (2a and 7a, respectively) or stepped portion having a decreasing thickness on at least a part of an outer edge of said coated portion, insulators are arranged to cover boundaries between said coated portion and said uncoated portion of said positive electrode, and one or both of said insulators provided on said current collector of said positive electrode have one end which is located on said inclined surface or on said stepped portion of said active material of said positive electrode and which is opposite to said inclined portion or stepped portion of one or both of said active materials formed on both surfaces of said current collector of said negative electrode, and have other end which is located on said uncoated portion of said positive electrode, wherein a combined total thickness of said insulator, a thickness of said active material of said positive electrode at a portion where said one end of said insulator is located, and a thickness of said active material of said negative electrode at a portion that is opposite to said one end of said insulator is less than a combined total thickness of a flat portion of said active material of said positive electrode and a thickness of said flat portion of said active material of said negative electrode..