A refill comprising: a staple receiving portion comprising: a bottom wall configured to allow a stack of connected staples to be placed thereon; a first side wall erected from the bottom wall (20, 120); a second side wall erected from the bottom wall (20, 120) and positioned at a location opposing the first side wall; a front wall connecting the first side wall with the second side wall and having a discharging port for discharging the connected staples, wherein the front wall is erected from the bottom wall with the discharging port interposed therebetween; and a rear wall erected from the bottom wall, connecting the first side wall with the second side wall, and positioned at a location opposing the front wall, wherein the staple receiving portion is provided with an opening at a location thereon opposing the bottom wall; and a cover member configured to be fitted in the opening to cover the connected staples from above and also to descend along a stacking direction of the connected staples inside the staple receiving portion as the connected staples are discharged through the discharging port and thus the connected staples are reduced, wherein the cover member has a protrusion portion (590, 591) protruding upward from an upper surface thereof, and wherein the protrusion portion (590, 591) is arranged at a location on the upper surface, which is closer to the rear wall than the middle portion thereof in a discharging direction of the connected staples, characterized in that the protrusion portion (590, 591) has a top portion configured to be positioned above upper edge portions of the first and second side walls (24, 26) when the maximum number of the connected staples is stacked in the staple receiving portion, and the cover member is placed on the upper most layer of the connected staples accommodated in the staple accommodating portion, and is attached to the staple accommodating portion. a staple receiving portion comprising: a bottom wall configured to allow a stack of connected staples to be placed thereon; a first side wall erected from the bottom wall (20, 120); a second side wall erected from the bottom wall (20, 120) and positioned at a location opposing the first side wall; a front wall connecting the first side wall with the second side wall and having a discharging port for discharging the connected staples, wherein the front wall is erected from the bottom wall with the discharging port interposed therebetween; and a rear wall erected from the bottom wall, connecting the first side wall with the second side wall, and positioned at a location opposing the front wall, wherein the staple receiving portion is provided with an opening at a location thereon opposing the bottom wall; and a bottom wall configured to allow a stack of connected staples to be placed thereon; a first side wall erected from the bottom wall (20, 120); a second side wall erected from the bottom wall (20, 120) and positioned at a location opposing the first side wall; a front wall connecting the first side wall with the second side wall and having a discharging port for discharging the connected staples, wherein the front wall is erected from the bottom wall with the discharging port interposed therebetween; and a rear wall erected from the bottom wall, connecting the first side wall with the second side wall, and positioned at a location opposing the front wall, wherein the staple receiving portion is provided with an opening at a location thereon opposing the bottom wall; and a cover member configured to be fitted in the opening to cover the connected staples from above and also to descend along a stacking direction of the connected staples inside the staple receiving portion as the connected staples are discharged through the discharging port and thus the connected staples are reduced, wherein the cover member has a protrusion portion (590, 591) protruding upward from an upper surface thereof, and wherein the protrusion portion (590, 591) is arranged at a location on the upper surface, which is closer to the rear wall than the middle portion thereof in a discharging direction of the connected staples, characterized in that the protrusion portion (590, 591) has a top portion configured to be positioned above upper edge portions of the first and second side walls (24, 26) when the maximum number of the connected staples is stacked in the staple receiving portion, and the cover member is placed on the upper most layer of the connected staples accommodated in the staple accommodating portion, and is attached to the staple accommodating portion.