A heat generating element includes at least one PTC element, contact sheets flatly lying against the PTC element on either side, a housing which forms at least one opening for receiving the at least one PTC element and which has a terminal side at which contact tongues allocated to the contact sheets are exposed. The device also has a wedge element with a broader and a narrower end face which are connected to each other via first and second wedge surfaces, the first wedge surface extending in parallel to one of the contact sheets and lying against it with a slide plate being inserted, and the second wedge surface being exposed at the outer side of the housing. A heat generating element less susceptible to damages during assembly has a slide plate connected to the housing.