Abstract: A stapler includes an elongate loader which receives sticks of staples with a back width in a particular range of widths and a slider attached to a rail and mobile between a first position in which it allows access to the loader and a second position in which the rail passes between the legs of a stick of staples installed in the loader to guide them towards a driver. The rail is positioned on the cover and has transverse dimensions such that it can pass freely between the legs of the staples. Cams are provided to move the rail laterally when the slider moves from its first position to its second position.