Watch case comprising: a case middle (60); removable horns (40); at least one nut (10) inserted in a housing (62) formed in the thickness of the case middle, a nut portion (14) protruding to the outside of the case middle; a removable horn retaining screw (20) engaged in each said nut (10). By virtue of the invention, the thickness required to accommodate the screw (20) is not supported by the case middle (60) but by the projecting nut portion (14); it is thus possible to make case middles that are very thin, and therefore lightweight, while at the same time ensuring attachment of the horns (40) to the case middle (60).