Abstract: A panel fastening device has a baseplate and a latch with a hook emerging on one side of the baseplate, oriented towards this baseplate, and this latch is longitudinally movable on the referred baseplate, and they are manufactured on a non-ferromagnetic material. The latch has a magnet or a magnetic part, so that such magnet permits the movement of the latch towards a closing position on the baseplate when the panel is set in the assembling position and the magnet approaches the metal framework for supporting roof or wall panels that carry the closure device.