In a camshaft adjusting device for adjusting a phase position of a camshaft relative to a crankshaft of an internal combustion engine with a gear mechanism including at least three drive connections, a locking element is provided, with which at least two of the at least three drive connections, can be locked to one another in a rotationally fixed manner depending on operating conditions for retaining a particular phase position of the camshaft relative to the crankshaft of the internal combustion engine.