A case for a secondary battery, comprising: a lower case having an opened upper portion and an empty space therein; and an upper case having an opened lower portion and an empty space therein, wherein a coupling part that is a region in which an upper region of the lower case and a lower region of the upper case contact each other so as to be coupled to each other is provided, a lower case uneven part is provided in the upper region of the lower case in at least partial region of the coupling part, and an upper case uneven part having a shape corresponding to that of the lower case uneven part is provided in a region of the upper case, which faces the lower case uneven part, wherein, the upper region of the lower case has a predetermined thickness (t 1), and the lower case uneven part has a variable height in a direction of the thickness (t 1) of the upper region of the lower case; the lower case uneven part comprises a first lower case uneven part provided in one region of the upper region of the lower case, and a second lower case uneven part provided in an opposite region of the region, in which the first lower case uneven part is provided, in the other region of the upper region of the lower case; and each of an inner end region and an outer end region of the first lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case is recessed downward, an intermediate region of the first lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case protrudes upward, each of an inner end region and an outer end region of the second lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case protrudes upward, and an intermediate region of the second lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case is recessed downward. a lower case having an opened upper portion and an empty space therein; and an upper case having an opened lower portion and an empty space therein, wherein a coupling part that is a region in which an upper region of the lower case and a lower region of the upper case contact each other so as to be coupled to each other is provided, a lower case uneven part is provided in the upper region of the lower case in at least partial region of the coupling part, and an upper case uneven part having a shape corresponding to that of the lower case uneven part is provided in a region of the upper case, which faces the lower case uneven part, wherein, the upper region of the lower case has a predetermined thickness (t 1), and the lower case uneven part has a variable height in a direction of the thickness (t 1) of the upper region of the lower case; the lower case uneven part comprises a first lower case uneven part provided in one region of the upper region of the lower case, and a second lower case uneven part provided in an opposite region of the region, in which the first lower case uneven part is provided, in the other region of the upper region of the lower case; and each of an inner end region and an outer end region of the first lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case is recessed downward, an intermediate region of the first lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case protrudes upward, each of an inner end region and an outer end region of the second lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case protrudes upward, and an intermediate region of the second lower case uneven part in the direction of the thickness (t 1) of the upper region of the lower case is recessed downward.