Abstract: A stapler comprises a base (1), a staple pin track (2), a top blade assembly (3), a hinge (4) and an upper cover (5). Tail ends of the staple pin track, the top blade assembly and the upper cover are all hingedly connected to a tail end of the base. A first guide part is disposed on a side wall of the upper cover, and one end of the hinge is slidably connected to the first guide part. The first guide part is set in a structure that when the upper cover is pressed, one end of the hinge can move to the tail end of the upper cover and press downwards. A second guide part is disposed on the side wall of the base, and the other end of the hinge is slidably connected to the second guide part. The second guide part is set in a structure that when the upper cover is pressed, the other end of the hinge can move to a front end of the base, and when the upper cover is opened, the other end of the hinge is separated from the base.