A steering wheel lock apparatus having high reliability. The steering wheel lock apparatus (1) includes a lock pin (21), which engages a steering wheel (5), a motor (23), which moves the lock pin, and a control circuit (31), which controls the motor. The control circuit includes a power supply line (72b), which provides locking current to the motor for locking the steering wheel. A breaker circuit (61) selectively breaks the power supply line when a user operates an ignition switch knob (81) to start the vehicle.