A device and method for implementing a hybrid drive mechanism, which stands out by a very low construction expenditure, a small need of installation space, low cost of parts and a simple and effective maneuverability. Particularly, the start and stop of the internal combustion engine should stand out by simplicity and reliability. By a development of a one clutch, hybrid drive mechanism or without an additional second clutch, the needed installation space and costs can be minimized and by control, the expenditure for and the complexity of the control or regulation of a hybrid drive mechanism are considerably reduced. An electric machine (4) is disposed between a single clutch (2) situated between the internal combustion engine and a mechanical transmission (5) so that the electric machine can transmit a positive or negative torque directly to a transmission input shaft of the mechanical transmission.