Staple refill, stapler, and cartridge

A staple refill comprising:

• a refill body accommodating sheet-type connected staples, the refill body including a bottom wall, a right wall provided on a right side of the bottom wall and formed with a vertically extending right guide slot, and a left wall provided on a left side of the bottom wall and formed with a vertically extending left guide slot, the sheet-type connected staples being directly contained by the bottom wall, the right wall, and the left wall of the refill body;
• and
• a pressing member provided in the refill body in a movable manner to press the sheet-type connected staples, the pressing member including a guide shaft guided along the right and left guide slots,
• wherein the guide shaft includes a right end portion protruding outside the right wall through the right guide slot, and a left end portion protruding outside the left wall through the left guide slot.