A device is disclosed for adjusting the tension of the strings of a string instrument, especially a guitar, preferably an electric guitar, or a bass, preferably an electric bass, said strings being secured at a first end to a winding mechanism and at a second end to another mount, said device having at least one motor, a gear connected to the motor and flexible shafts connected to the gear for transmission of a rotational movement generated by the combination of the motor and the gear to the winding mechanism whereby the device has fewer motors than there are strings on the string instrument.With this device it is possible to arrange a drive for automatic adjustment of the tension of the strings of the string instrument in a space-saving manner and in the smallest possible amount of space.