A suction device for retaining and/or transporting objects, comprising: a main supporting body; at least one operating plate mounted on the main supporting body, the operating plate having an operating surface, and in which a plurality of suction holes is made; suction means in fluid connection with said plurality of suction holes for sucking air through them; wherein the operating plate is removably associated with the main supporting body; the main supporting body has at least one first connecting face; and the operating plate has a second connecting face placed on the opposite side to the operating surface and which is coupled to the first connecting face when the operating plate is associated with the main supporting body; the suction device further comprising one or more magnets and one or more ferromagnetic bodies, each ferromagnetic body being magnetically coupled to one or more magnets when the operating plate is associated with the main supporting body for keeping the operating plate fastened to the main supporting body, each magnet and the ferromagnetic body magnetically coupled to it being constrained respectively one to the operating plate, the other to the main supporting body, the suction device further comprising one or more fastening guides and one or more fastening elements; wherein: each fastening element is couplable to a fastening guide during the coupling of the operating plate to the main supporting body, each fastening element and the fastening guide to which it is couplable, being fixed one to the operating plate and the other to the main supporting body; each fastening guide is shaped in such a way as to guide, by the interaction with the corresponding fastening element, a shifting of the operating plate relative to the main supporting body along a coupling trajectory which extends between a coupling start position in which the one or more magnets and the one or more ferromagnetic bodies are magnetically substantially uncoupled, and a coupling completion position in which the one or more magnets and the one or more ferromagnetic bodies are magnetically coupled; characterised in that said coupling trajectory has a main component of extension which lies in a plane perpendicular to a reference line that, with the operating plate associated with the main supporting body, corresponds to the line along which the distance of a central point of each magnet from the ferromagnetic body coupled to it is at its minimum. a main supporting body; at least one operating plate mounted on the main supporting body, the operating plate having an operating surface, and in which a plurality of suction holes is made; suction means in fluid connection with said plurality of suction holes for sucking air through them; wherein the operating plate is removably associated with the main supporting body; the main supporting body has at least one first connecting face; and the operating plate has a second connecting face placed on the opposite side to the operating surface and which is coupled to the first connecting face when the operating plate is associated with the main supporting body; the suction device further comprising one or more magnets and one or more ferromagnetic bodies, each ferromagnetic body being magnetically coupled to one or more magnets when the operating plate is associated with the main supporting body for keeping the operating plate fastened to the main supporting body, each magnet and the ferromagnetic body magnetically coupled to it being constrained respectively one to the operating plate, the other to the main supporting body, the suction device further comprising the main supporting body has at least one first connecting face; and the operating plate has a second connecting face placed on the opposite side to the operating surface and which is coupled to the first connecting face when the operating plate is associated with the main supporting body; the suction device further comprising one or more magnets and one or more ferromagnetic bodies, each ferromagnetic body being magnetically coupled to one or more magnets when the operating plate is associated with the main supporting body for keeping the operating plate fastened to the main supporting body, each magnet and the ferromagnetic body magnetically coupled to it being constrained respectively one to the operating plate, the other to the main supporting body, the suction device further comprising one or more fastening guides and one or more fastening elements; each fastening element is couplable to a fastening guide during the coupling of the operating plate to the main supporting body, each fastening element and the fastening guide to which it is couplable, being fixed one to the operating plate and the other to the main supporting body; each fastening guide is shaped in such a way as to guide, by the interaction with the corresponding fastening element, a shifting of the operating plate relative to the main supporting body along a coupling trajectory which extends between a coupling start position in which the one or more magnets and the one or more ferromagnetic bodies are magnetically substantially uncoupled, and a coupling completion position in which the one or more magnets and the one or more ferromagnetic bodies are magnetically coupled; characterised in that said coupling trajectory has a main component of extension which lies in a plane perpendicular to a reference line that, with the operating plate associated with the main supporting body, corresponds to the line along which the distance of a central point of each magnet from the ferromagnetic body coupled to it is at its minimum.