A gear lever locking device to be installed inside a gear lever cover panel is characterized in that it comprises an auxiliary connector transverse stud and a gear lever connector which is slidable in accordance with the movement of a gear lever. On an auxiliary connector, there is provided a plurality of stud holes for use with a gear lever transverse stud having a stud end pushing mechanism. The stud end pushing mechanism receives the force exerted from a locking mechanism by a pressing means. The gear lever locking device according to the present invention includes screw guards and a cover wall that have been designed to cover a locking mechanism installation portion to prevent any removal of fastening screws or a gear sling, to prevent disassembling or breaking of the locking mechanism of the gear lever locking device to improve safety.