There is provided a driving method for an ink jet head comprising one or more discharge ports for discharging the ink, a substrate incorporating one or more heat generating elements for generating the heat energy, each of which is provided correspondent to each discharge port, and a support plate or casing on which the substrate is mounted. The method is characterized in that when recording an image with the ink jet head in which the heat energy for discharging the ink in accordance with an image signal is generated in the heat generating elements, and the thermal resistance value passing through said support plate or casing is lower than that not passing through the support plate or casing among the thermal resistance between the substrate and externally of the apparatus (E.sub.max -E)/(V.sub.max -V) is controlled to be always substantially constant whenever E.noteq.E.sub.max, providing that the thermal energy generated in the substrate is E.sub.max when the ink jet head discharges the ink with a maximum volume of V.sub.max, the ink discharge volume in accordance with the image signal is V, and the heat energy generated in the substrate at this time is E.