An adjusting device for the rotational position of the camshaft of a reciprocating piston engine relative to the crankshaft has a variator which is designed as a three-shaft transmission having a fixed-to-the-crankshaft input shaft, a fixed-to-the-camshaft output shaft, and an adjusting shaft. The adjusting shaft is coupled nonrotatably to the rotor of a servomotor. To limit the torsional angle between the camshaft and the crankshaft, the adjusting device has limit stops. The servomotor is connected to a control circuit which is designed for controlling the phase velocity of the torsional angle.