A heating device intended to heat body, such as fluid contained in fluid circuit, the device including at least one electric heating element, as well as at least one control module to electrically power the heating element, the heating element being formed by propulsive winding circuit of direct-current electric motor which, when it is electrically powered by a direct supply voltage, generates drive force which tends to drive the motor in direction of displacement determined by the polarity of the supply voltage, and the control module including activation mode called heating oscillating mode, according to which the control module causes a warm-up of the propulsive winding circuit by Joule effect by applying at the terminals of the winding circuit an alternating supply voltage whose polarity switches, alternately and automatically, according to predetermined frequency called heating frequency, from a first polarity to opposite second polarity.