Secondary battery

A secondary battery includes an electrode assembly in a pouch case, the pouch case includes a first case part having a first accommodating part in which a part of the electrode assembly is embedded, and a second case part having a second accommodating part in which the remaining part of the electrode assembly is accommodated, the first case part and the second case part contact each other along an edge portion surrounding the first and second accommodating parts and are sealed by a sealing part having a band shape on at least a part of the edge portion, the sealing part includes a first sealing part having a first width and a second sealing part having a second width smaller than the first width, and a central portion of the second sealing part in a longitudinal direction coincides with a central portion of a long side of the electrode assembly.