A hydraulic camshaft adjuster for changing the control times of gas exchange valves of an internal combustion engine, designed as a vane cell camshaft adjuster. A control device inserted in the vane selectively opens and interrupts a flow connection between the working chambers. A locking device prevents relative motion between the rotor and the stator in that the rotor is fastened to the stator at a vane position. A switching valve, which has three working ports, a P port and a T port, can be moved into different control positions by an adjusting element,—wherein in the control position, the P port communicates with the working chambers via the A port, the B port is blocked at the switching valve, and the T port communicates with the control device of the vanes via the C port. In a control position provided as a starting strategy for the switching valve the A port communicates with the P port and the working chambers, the B port communicates with the T port and the working chambers, and the C port communicates with the control device of the vanes and the T port.