The invention relates to an electromagnetic locking device, particularly for the ignition switch or ignition lock of motor vehicles, with an electromagnetically-actuated locking plunger (2), formed as the armature (3) of a lift magnet (4) (solenoid) and arranged on the periphery (7) of the rotor (5) of an ignition switch, of the connecting shaft or of the locking cylinder of an ignition lock for an essentially-radial engagement with a cam (6) on the periphery of the rotor, of the shaft or of the locking cylinder. The invention is characterized in that the cam (6) is designed as a slide piece (9) and is guided in a recess (10) on the periphery (7) of the rotor, of the shaft or of the locking cylinder and can be displaced outwards under the pressure of a spring (11). In this way, it is guaranteed that the locking plunger (2) of the solenoid or lift magnet (4) can not stick in the recess (10) or in the guide sleeve (20) at the solenoid or the armature of the lift magnet (4). Because the cam (6) is designed as a spring-loaded slide piece (9) which is displaceably guided transverse to the longitudinal axis of the rotor (5), of the shaft or of the locking cylinder in a recess and is pushed outwards under pressure of a spring (11), the retaining force of the lift magnet (4) is reliably overcome after the power is switched off and the armature (3) with the locking plunger (2) is securely withdrawn from the locking position to the starting position.