A device for electrically adjusting the relative rotation of two shafts, particularly a camshaft (15) in relation to a crankshaft of an internal combustion engine is provided. The adjusting device includes an adjusting gear system which is embodied as a triple-shaft gear mechanism and is provided with a crankshaft-fixed input part, a camshaft-fixed output part, and an adjusting shaft (13) that is connected in a torsion-proof manner to an electric adjusting motor shaft (32) of an electric adjusting motor (3). The adjusting motor (3) is configured as a brushless DC motor having a housing-fixed stator (35) and a permanent magnet rotor (34). A high degree of adjustment accuracy and adjustment speed are provided with minimal space requirements and low power consumption. This is achieved through the use of a double eccentric gear mechanism (2) and a double planetary gear mechanism, which are provided with a speed reduction of up to about 1:250 and low friction, as an adjusting gear system while using a highly inductive permanent magnet rotor for the adjusting motor (3).