An adjusting device for the rotational position of the camshaft of a reciprocating piston engine relative to the crankshaft, has an actuator for adjusting the rotational position that is connected into a control circuit. The control circuit has a controller, which is linked to a data memory, in which controller coefficients for a transfer function of the controller are stored. The data memory has at least two memory areas in which various sets of controller coefficients are stored. The control circuit is connectable with the aid of a mode selector, optionally or alternately, in such a way to one of the data memory areas that the controller coefficient set stored in the particular data memory area is used for the control. A device for ascertaining the operating state of the adjusting device and/or of the reciprocating piston engine is connected to the mode selector in such a way that the controller coefficient set used in the particular case for the control is dependent on the operating state.