An object-carrying device comprising: a fixed frame engageable on a vehicle; a mobile frame, predisposed to support at least an object to be transported and operatively associated to the fixed frame and slidable thereon between a non-use position, in which the mobile frame lies on at least a plane which is substantially parallel to the lie plane of the fixed frame, and a use position in which the mobile frame lies on a transversal plane to the lie plane of the fixed frame; a blocking mechanism comprising engaging means operatively associated to the object-carrying device for reciprocally engaging the fixed frame and the mobile frame, and being arranged on the mobile frame, characterised in that the engaging means are operatively active on the fixed frame and comprise: at least a hook element engaged to the mobile frame of the object-carrying device, the hook element being mobile between an engaged position, in which it engages the fixed frame to maintain the fixed frame coupled to the mobile frame, and a disengaged position, in which it does not engage the fixed frame and the mobile frame is free with respect to the fixed frame; at least a first manoeuvring appendage engaged to the hook element in order for the hook element to be moved at least from the engaged position to the disengaged position, wherein the hook element exhibits: at least a contrast portion predisposed to interact with the fixed frame to keep the hook element in the engaged position; at least a pushing portion inclined with respect to the contrast portion, the pushing portion interacting with the fixed frame to bring the hook element towards the disengaged position when the mobile frame is coupled to the fixed frame, and wherein the hook element and the first manoeuvring appendage are made in a single piece and define together a plate structure having a substantially L-shaped conformation, the hook element developing through a terminal portion of the mobile frame, the contrast portion and the pushing portion being arranged on an opposite side to the first manoeuvring appendage. a fixed frame engageable on a vehicle; a mobile frame, predisposed to support at least an object to be transported and operatively associated to the fixed frame and slidable thereon between a non-use position, in which the mobile frame lies on at least a plane which is substantially parallel to the lie plane of the fixed frame, and a use position in which the mobile frame lies on a transversal plane to the lie plane of the fixed frame; a blocking mechanism comprising engaging means operatively associated to the object-carrying device for reciprocally engaging the fixed frame and the mobile frame, and being arranged on the mobile frame, characterised in that the engaging means are operatively active on the fixed frame and comprise: at least a hook element engaged to the mobile frame of the object-carrying device, the hook element being mobile between an engaged position, in which it engages the fixed frame to maintain the fixed frame coupled to the mobile frame, and a disengaged position, in which it does not engage the fixed frame and the mobile frame is free with respect to the fixed frame; at least a first manoeuvring appendage engaged to the hook element in order for the hook element to be moved at least from the engaged position to the disengaged position, wherein the hook element exhibits: at least a contrast portion predisposed to interact with the fixed frame to keep the hook element in the engaged position; at least a pushing portion inclined with respect to the contrast portion, the pushing portion interacting with the fixed frame to bring the hook element towards the disengaged position when the mobile frame is coupled to the fixed frame, and wherein the hook element and the first manoeuvring appendage are made in a single piece and define together a plate structure having a substantially L-shaped conformation, the hook element developing through a terminal portion of the mobile frame, the contrast portion and the pushing portion being arranged on an opposite side to the first manoeuvring appendage.