A locking device for locking a movable module of an electronic apparatus disclosed by the invention mainly includes a control member and a latch connected to the control member. The control member is selectively movable between a first position for locking the movable module and a second position for releasing the movable module. When the latch stops at the first position, it also latches onto an operational interface or a mechanism component so as to prevent the user from electrically or mechanically operating the apparatus.