To hinder a person not having an ignition key from making undue operation to a manual unlocking device for unlocking the motor-driven parking brake.

Even if any person tries to unlock a parking brake device by pulling a manual unlock lever 82 of a manual unlocking device 20 when an ignition key of a vehicle is drawn off from a key cylinder, an engagement part 91a of a lock member 91 of a manual unlocking prohibition device 36 is engaged with the part 82c to be engaged of the manual unlock lever 82, so that undue person with no ignition key can not unlock the parking brake device through undue operation to the manual unlocking device 20, and it is possible to avoid such an inconvenient occurrence that the parking brake device is unlocked while the driver is away from the vehicle and the vehicle is stolen. When the ignition key is inserted into the key cylinder, a solenoid 95 is energized to put a cam member 93 in movement to cause the lock member 91 to swing downward, and it is made practicable to unlock the parking brake device by pulling the manual unlock lever 82.