Curved magnetic guide for guiding the chain of a conveyor chain along a curvilinear transport direction (A-A), wherein said chain is at least partially made of a magnetisable material, comprises a plurality of links, said links are hinged together at respective hinging portions by means of respective pins and each link is equipped with a plate-shaped portion defining a transport surface, and is closed to form a loop defining a forward branch and a return branch, wherein said guide comprises: - at least one pair of first guide profiles that are arranged spaced apart and that extend in a continuous manner along a respective development direction (B-B, C-C) concentric to said curvilinear transport direction (A-A), - a support structure for supporting said first guide profiles and that comprises at least a plurality of box-shaped bodies, said box-shaped bodies being arranged in succession one after the other and spaced apart from one another along said curvilinear transport direction (A-A), wherein each of said box-shaped bodies houses at least one magnetic body therein and has an upper surface and a lower surface opposite one another, - wherein said magnetic bodies are adapted for interacting with said links or with their hinging pins to attract the links of said chain with said part of their plate-shaped portions against the respective said sliding surfaces defined by said first guide profiles, said curved magnetic guide being characterized in that said upper surface is provided with a pair of first constraining projections that are spaced apart and faced with distances between centres substantially equal to the distance between said development directions (B-B, C-C), wherein said first constraining projections of said plurality of box-shaped bodies define two rows of first constraining projections that extend, spaced apart from one another, along a respective said development direction (B-B, C-C), - wherein each of said box-shaped body comprises a closed box-shaped portion delimited by said upper surface and by said lower surface thereof and in which at least one said magnetic body is contained; and in that each of said first guide profiles of said at least one pair is coupled with said first constraining projections aligned along one of said two rows, and in that said guide defines a forward guide for guiding the forward branch of said chain, said forward guide comprising a forward channel, which is adapted for receiving the hinging portions of said links and which is laterally delimited by said first guide profiles of said at least one pair, wherein said first guide profiles each defines a sliding surface for at least one part of said plate-shaped portion of said links to slide thereon. - at least one pair of first guide profiles that are arranged spaced apart and that extend in a continuous manner along a respective development direction (B-B, C-C) concentric to said curvilinear transport direction (A-A), - a support structure for supporting said first guide profiles and that comprises at least a plurality of box-shaped bodies, said box-shaped bodies being arranged in succession one after the other and spaced apart from one another along said curvilinear transport direction (A-A), wherein each of said box-shaped bodies houses at least one magnetic body therein and has an upper surface and a lower surface opposite one another, - wherein said magnetic bodies are adapted for interacting with said links or with their hinging pins to attract the links of said chain with said part of their plate-shaped portions against the respective said sliding surfaces defined by said first guide profiles, said curved magnetic guide being characterized in that said upper surface is provided with a pair of first constraining projections that are spaced apart and faced with distances between centres substantially equal to the distance between said development directions (B-B, C-C), wherein said first constraining projections of said plurality of box-shaped bodies define two rows of first constraining projections that extend, spaced apart from one another, along a respective said development direction (B-B, C-C), - wherein each of said box-shaped body comprises a closed box-shaped portion delimited by said upper surface and by said lower surface thereof and in which at least one said magnetic body is contained; and in that each of said first guide profiles of said at least one pair is coupled with said first constraining projections aligned along one of said two rows, and in that said guide defines a forward guide for guiding the forward branch of said chain, said forward guide comprising a forward channel, which is adapted for receiving the hinging portions of said links and which is laterally delimited by said first guide profiles of said at least one pair, wherein said first guide profiles each defines a sliding surface for at least one part of said plate-shaped portion of said links to slide thereon.