The invention relates to a device for the filling of bags in automatic machines for the formation, filling and closing in a continuous process of bags from a tubular mesh, of those comprising a tubular body outside which the storage of tubular mesh is assembled, the device comprising means for the conveyance of individual pieces of large fruit and vegetable products, such as melons, watermelons or the like, from a loading position to a delivery position, and means for the holding and transfer, one by one, of the individual pieces conveyed to the delivery position, which comprise a head for the holding and subsequent release of the pieces and a mechanism for transmitting to the head a movement the path of which comprises a vertical downward section, of a sufficient length to convey the held piece through the inside of the tubular body of the machine towards the mouth of a bag open at the upper part, and such that the piece is accompanied in its entire downward path.