An adjusting device for camshafts of motor vehicles has a stator having radial inwardly projecting stays and a rotor having vanes projecting into spaces defined between the stays of the stator. The rotor is rotatable relative to the stator and the vanes of the rotor are loadable on opposed sides with a pressure medium. The rotor is lockable relative to the stator in a locked position, wherein the stator has at least one locking bore and the rotor has a locking element having a locking position in which the locking element engages the locking bore and locks the rotor in the locked position. The locking element is moveable by the pressure medium from the locking position into a release position.