A heating device having an electrical heating conductor arrangement integrated in a flexible heating body and connected to a supply voltage by a connector cable. A heating circuit is connected to the above and further elements, including a first control element embodied for a heating current and a drive circuit for varying the heating current and regulating the temperature, connected to the first controller and having a safety circuit. According to this invention, increased safety features are achieved, whereby the safety circuit has an error sensor device and an additional control element driven by the safety circuit and is arranged in series with the first control element in the heating circuit. The safety circuit also or only responds to an error in the control circuit and interrupts the heating current by driving the additional control element.