Abstract: The prompting device for safety belts in a motor vehicle comprises a sensor for sensing battery voltage drop during actuation of a starter of the motor vehicle. The sensed voltage drop is converted into a binary signal which is stored in a storing device. After termination of the starting process when the engine is running and driving a loading generator, the stored binary signal activates via a timing switch an optical and/or acoustical indicator prompting the user of the vehicle to fasten the seat belts.