In an adjusting mechanism having an adjusting device for adjusting a phase position of a camshaft in relation to a crankshaft of an internal combustion engine, and a drive gear driven by the crankshaft, for driving the camshaft, a four-shaft transmission configured as an epicyclic summing gear train for the adjustment of the phase position of the camshaft is provided in a housing from which four shafts extend and two of them are concentric for connection to corresponding shafts of a control motor capable of applying different braking torques to the two concentric shafts.