27 of the locking apparatus 2 is so pushed as to pass through the hole 16 of the inner wall plate 15 of the housing 14 to press against the press button 41 of the hand brake lever 4 with a view to facilitating a correct entry of the key 3 into the locking apparatus 2 a plurality of pin balls 24 and the elastic element 26 are provided to facilitate the movements of the lock core 21 inside the locking apparatus 2 when the pin balls 24 are caused to move by the key 3 which is inserted into the locking apparatus 2 the lock core 21 is pushed to move accordingly as soon as the lock core 21 is relieved of the external force exerting thereon the lock core 21 is forced to return to its original position by the elastic force of the elastic element 26 as illustrated in fig2 the key 3 is inserted into the lock core 21 of the locking apparatus 2 by a driver when the inserted key 3 is pushed further into the lock core 21 as shown in fig3 the lock core 21 is caused to move deeper into the locking apparatus 2 in a straight line manner so as to cause the shaft 27 to press against the press button 41 of the hand brake lever 4 it must be noted here that the extent of such straight line movement of the lock core 21 is limited by the length of of the groove 23.