A locking apparatus used for controlling a movable chain, strip or strap-shaped object (71) comprising a support frame; a roll shaft (6) with a friction surface or a sprocket pitch slot (64), the roll shaft (6) being fixedly connected to a support rod (66), and one end of the support rod (66) being pivotally connected onto the support frame; a pawl (62) disposed above the roll shaft (6) and capable of rotating around one end; and a pressurization body (3) opposite to the roll shaft (6) along a transverse direction, thereby forming a roll gap between the roll shaft (6) and the pressurization body (3). The roll shaft (6) can freely rotate when the roll shaft (6) is in a middle state. When the roll shaft (6) is forced to downwards pivot until a ratchet disposed on a contact base (65) engages with a ratchet (6302) of the roll shaft (6) to prevent the rotation of the roll shaft (6), the object (71) can be locked. When the roll shaft (6) is forced upwards pivot until the ratchet (6302) of the roll shaft (6) abuts against the pawl (62), the roll shaft (6) can still rotate; when the object (71) changes the direction to downwards move, the pawl (62) engages with the ratchet (6302) of the roll shaft (6) to prevent the rotation of the roll shaft (6) and loses the engagement with the ratchet (6302) of the roll shaft (6) as the roll shaft (6) downwards pivots.