A locking device for a container having a hinged lid, comprises a base unit adapted to be fixed to the container and a pivotable unit mounted to the base unit and pivotally movable between open and closed positions. The base unit includes a locking mechanism comprising a casing, a rotatable shaft, a blocking member fixed to the shaft and disposed in the casing, and a rolling member. The pivotable unit is mounted to the shaft of the base unit. The rolling member is provided to move within the casing between a blocking position wherein the rolling member blocks movement of the pivotable unit relative to the casing to prevent unauthorized opening of the lid, and a release position wherein the rolling member moves away from the blocking member to permit the movement of the blocking member relative to the casing thereby permitting opening of the lid.