Abstract: An automatically disengaging locking device is provided for use on a container having a hinged lid pivotable between open and closed positions. The locking device consists of a housing mounted to the side surface of the container, and a latch securable to the lid having a portion which extends through an opening in the housing when the lid is closed. The locking device further includes a keeper element disposed within the housing for engaging the lower portion of the latch to secure the lid in its closed position, a manual release mechanism comprising a plunger for allowing the selective disengagement of the keeper from the latch, and an automatic release mechanism operative to disengage the keeper from the latch when the container is moved for emptying. IN a first embodiment the automatic release mechanism comprises a pendulum, and in a second embodiment the automatic release mechanism comprises a rolling keeper pin.