A parking brake especially for an automotive automatic gearbox or an automotive automated manual gearbox. The parking brake comprises a blocking device that blocks or unblocks the gearbox in response to an actuation signal triggered by an actuation device. The blocking device is brought into the blocking position by actuating a spring accumulator (10) and the blocking device is released from the blocking position by either hydraulic or pneumatic pressure while simultaneously pretensioning the spring accumulator (10). The parking brake is further provided with a mechanically actuating locking device (40) for maintaining the blocking device in the non-blocking condition, and with an electromagnet (40) that can be supplied with current and that maintains the locking device (40) in the locking position. The parking brake is further characterized in that the locking device (40) is mechanically actuated by the blocking device when the blocking position is released and is maintained in the locking position by the electromagnet (30) that is supplied with current.