Abstract: The invention relates to a case assembly for antenna amplifying system, an antenna amplifying system and a mast antenna incorporating such a system. According to the invention, the case assembly for antenna amplifying system having a general shape elongated along a longitudinal axis (34) comprises a control module (16) and two amplifying modules (9a, 9b) aligned therewith along the longitudinal axis (34), the control module (16) and both amplifying modules (9a, 9b) each comprising two longitudinal lateral walls (11a, 11b, 11c, 12a, 12b, 12c), an upper surface (36a, 36b, 36c) and a lower surface (37a, 37b, 37c) and having a small thickness.