The invention relates to a system for aiding in the replacement of a mould of a molding unit of a machine for manufacturing containers, comprising at least one device (16) for transporting a joined mould (18) forming a transportable unit subassembly, said transport device (16) comprising at least one robotic arm (96) for positioning, in space along a trihedron (X, Y, Z) and with respect to the molding unit (12), a means (76) for handling at least one joined mould (18) so as to carry out the replacement of said at least one mould (18) of said molding unit (12).