Such a switching device is known from GB-B-2,211,353. Snap-action switching springs of a switching device should have a satisfactory conductivity for electric current. However, the electric current generates heat in the switching springs. When such switching springs are used in appliances which in addition operate at a high ambient temperature, the heat produced in the switching is considerable, as result of which the total temperature of the switching spring becomes very high. The switching springs should therefore have an adequate creep strength to prevent relaxation. To this end the springs are manufactured from hardened chrome-nickel steel. However, such a material has a comparatively high specific resistance (approximately 730 n.OMEGA.m), as a result of which the heat generation in the switching spring even increases. If the switching device is used in appliances such as flat-irons, which operate both with high current intensities and at a high ambient temperature, the resulting heat generation may lead to such a high temperature that it may give rise to creepage of, particularly, the mechanically loaded parts, specifically the bent tongue, which is under compressive stress. This causes the compressive stress to decrease, as a result of which the switching device no longer performs satisfactorily. For large current intensities the free end portions of the tongues, which are hooked together so as to be pivotal, may even become welded to one another, so that the spring is impeded in its movement and no longer performs its switching function.