a method and an apparatus for increasing the temperature gradient of a magneto - calorific thermal generator comprising magneto - calorific elements subjected to a magnetic field variation . at least one of a pre - heating and pre - cooling of the magneto - calorific elements is carried out to modify the initial temperature before and / or during the magnetic field variation before reaching the maximum and / or minimum field value . the method and apparatus may be employed in heating , tempering , air conditioning , refrigeration and other industrial or domestic applications .