Adjustment device for adjusting the relative rotational angle position of a camshaft in relation to a crankshaft of an internal combustion engine, the device comprising an adjustment mechanism, which is provided as a triple-shaft transmission and which has an input part fixed to the crankshaft, an output part fixed to the camshaft, and an adjustment shaft connected to an adjustment motor shaft of an adjustment motor, wherein the adjustment motor comprises an electric motor and is placed spatially separated from the adjustment shaft and an adjustment rotation and torque generated by the motor is transmitted mechanically by a flexible shaft to the adjustment shaft.