A cartridge for a surgical instrument includes an end tool rotatable in at least one direction, the cartridge including a housing, a cover that covers one surface of the housing and has formed thereon a staple hole through which a staple accommodated in the housing is ejected to the outside, a working member arranged inside the housing and configured to move relative to the housing in a first direction that is a lengthwise direction of the housing, a release member on which the staple is arranged, wherein, as the working member moves, the release member moves upward from a lower portion of the housing to an upper portion of the housing to eject the staple to the outside, and an elastic member that is arranged between the housing and the cover, and provides an elastic force in a direction in which the release member is moved downward.