the invention relates to a device for starting a motor vehicle motor . according to the invention , a slot is used for inserting the key which is usually closed by a spring - loaded cover . the key is displaced in the slot into various key positions , in order to control different functions of the motor or other ancillary devices in the vehicle . in order to ensure a compact construction which is easy to use , the inventive device prevents the key from turning in the slot and the key is displaced into at least three operating positions for the control functions which are axially staggered . after being inserted for a first operating distance , the key takes up an initial position , in which it is secured in the slot in a force - fit . in a subsequent second intermediate position , the key is secured in a positive fit which can be locked automatically . this prevents the manual withdrawal of the key . in order to remove the key , the latter is axially pushed into a third final position , in which the lock on the operating position can be released . during its course of operation , the key is axially spring - tensioned in the direction of the retaining position the operating position of the key determines the different vehicle functions .